diff --git a/bindings/python/mapnik_image.cpp b/bindings/python/mapnik_image.cpp
index 32384a034..f6c0550d0 100644
--- a/bindings/python/mapnik_image.cpp
+++ b/bindings/python/mapnik_image.cpp
@@ -164,6 +164,36 @@ boost::shared_ptr<image_32> open_from_file(std::string const& filename)
     throw mapnik::image_reader_exception("Unsupported image format:" + filename);
 }
 
+boost::shared_ptr<image_32> fromstring(std::string const& str)
+{
+    std::auto_ptr<image_reader> reader(get_image_reader(str.c_str(),str.size()));
+    if (reader.get())
+    {
+        boost::shared_ptr<image_32> image_ptr = boost::make_shared<image_32>(reader->width(),reader->height());
+        reader->read(0,0,image_ptr->data());
+        return image_ptr;
+    }
+    throw mapnik::image_reader_exception("Failed to load image from buffer" );
+}
+
+boost::shared_ptr<image_32> frombuffer(PyObject * obj)
+{
+    void const* buffer=0;
+    Py_ssize_t buffer_len;
+    if (PyObject_AsReadBuffer(obj, &buffer, &buffer_len) == 0)
+    {
+        std::auto_ptr<image_reader> reader(get_image_reader(reinterpret_cast<char const*>(buffer),buffer_len));
+        if (reader.get())
+        {
+            boost::shared_ptr<image_32> image_ptr = boost::make_shared<image_32>(reader->width(),reader->height());
+            reader->read(0,0,image_ptr->data());
+            return image_ptr;
+        }
+        throw mapnik::image_reader_exception("Failed to load image from buffer" );
+    }
+}
+
+
 void blend (image_32 & im, unsigned x, unsigned y, image_32 const& im2, float opacity)
 {
     im.set_rectangle_alpha2(im2.data(),x,y,opacity);
@@ -257,6 +287,10 @@ void export_image()
         .def("save", &save_to_file3)
         .def("open",open_from_file)
         .staticmethod("open")
+        .def("frombuffer",&frombuffer)
+        .staticmethod("frombuffer")
+        .def("fromstring",&fromstring)
+        .staticmethod("fromstring")
 #if defined(HAVE_CAIRO) && defined(HAVE_PYCAIRO)
         .def("from_cairo",&from_cairo)
         .staticmethod("from_cairo")
diff --git a/include/mapnik/factory.hpp b/include/mapnik/factory.hpp
index 012c5de84..343460792 100644
--- a/include/mapnik/factory.hpp
+++ b/include/mapnik/factory.hpp
@@ -31,42 +31,23 @@
 #include <map>
 
 namespace mapnik {
-template <typename key_type,
-          typename product_type>
-class default_factory_error
-{
-public:
-    struct factory_exception : public std::exception
-    {
-        const char* what() const throw()
-        {
-            return "uknown object type";
-        }
-    };
-    static product_type* on_unknown_type(const key_type&)
-    {
-        return 0;
-    }
-};
 
 template
 <
 typename product_type,
 typename key_type,
-typename product_creator=product_type* (*)(),
-template <typename,typename> class factory_error_policy=default_factory_error
->
+typename ...Args >
 class factory : public singleton<factory <product_type,
                                           key_type,
-                                          product_creator,factory_error_policy> >,
-                factory_error_policy <key_type,product_type>
+                                          Args...> >
 {
 private:
+    typedef  product_type* (*product_creator)(Args...);
     typedef std::map<key_type,product_creator> product_map;
     product_map map_;
 public:
 
-    bool register_product(const key_type& key,product_creator creator)
+    bool register_product(const key_type& key, product_creator creator)
     {
         return map_.insert(typename product_map::value_type(key,creator)).second;
     }
@@ -76,14 +57,14 @@ public:
         return map_.erase(key)==1;
     }
 
-    product_type* create_object(const key_type& key,std::string const& file)
+    product_type* create_object(const key_type& key, Args const&...args)
     {
         typename product_map::const_iterator pos=map_.find(key);
         if (pos!=map_.end())
         {
-            return (pos->second)(file);
+            return (pos->second)(args...);
         }
-        return factory_error_policy<key_type,product_type>::on_unknown_type(key);
+        return 0;
     }
 };
 }
diff --git a/include/mapnik/image_reader.hpp b/include/mapnik/image_reader.hpp
index dff902653..a3a6545e7 100644
--- a/include/mapnik/image_reader.hpp
+++ b/include/mapnik/image_reader.hpp
@@ -27,13 +27,16 @@
 #include <mapnik/image_data.hpp>
 #include <mapnik/config.hpp>
 #include <mapnik/noncopyable.hpp>
-
+#include <mapnik/factory.hpp>
+// boost
+#include <boost/optional.hpp>
 // stl
 #include <stdexcept>
 #include <string>
 
 namespace mapnik
 {
+
 class image_reader_exception : public std::exception
 {
 private:
@@ -59,9 +62,15 @@ struct MAPNIK_DECL image_reader : private mapnik::noncopyable
     virtual ~image_reader() {}
 };
 
-bool register_image_reader(std::string const& type,image_reader* (*)(std::string const&));
+template <typename...Args>
+bool register_image_reader(std::string const& type, image_reader* (* fun)(Args...))
+{
+    return factory<image_reader,std::string, Args...>::instance().register_product(type, fun);
+}
+
 MAPNIK_DECL image_reader* get_image_reader(std::string const& file,std::string const& type);
 MAPNIK_DECL image_reader* get_image_reader(std::string const& file);
+MAPNIK_DECL image_reader* get_image_reader(char const* data, size_t size);
 
 }
 
diff --git a/src/build.py b/src/build.py
index e6b9b9b8f..1c45abf1a 100644
--- a/src/build.py
+++ b/src/build.py
@@ -55,9 +55,10 @@ ABI_VERSION = env['ABI_VERSION']
 filesystem = 'boost_filesystem%s' % env['BOOST_APPEND']
 regex = 'boost_regex%s' % env['BOOST_APPEND']
 system = 'boost_system%s' % env['BOOST_APPEND']
+iostreams = 'boost_iostreams%s' % env['BOOST_APPEND']
 
 # clear out and re-set libs for this env
-lib_env['LIBS'] = ['freetype','z',env['ICU_LIB_NAME'],filesystem,system,regex]
+lib_env['LIBS'] = ['freetype','z',env['ICU_LIB_NAME'],filesystem,system,regex,iostreams]
 
 if env['PROJ']:
    lib_env['LIBS'].append('proj')
diff --git a/src/image_reader.cpp b/src/image_reader.cpp
index 22e476e27..3bacd7cac 100644
--- a/src/image_reader.cpp
+++ b/src/image_reader.cpp
@@ -27,18 +27,45 @@
 
 namespace mapnik
 {
-typedef factory<image_reader,std::string,
-                image_reader* (*)(std::string const&)>  ImageReaderFactory;
 
-
-bool register_image_reader(std::string const& type,image_reader* (* fun)(std::string const&))
+inline boost::optional<std::string> type_from_bytes(char const* data, size_t size)
 {
-    return ImageReaderFactory::instance().register_product(type,fun);
+    typedef boost::optional<std::string> result_type;
+    if (size >= 4)
+    {
+        unsigned int magic = (data[0] << 24) | (data[1] << 16) | (data[2] << 8) | data[3];
+        if (magic == 0x89504E47U)
+        {
+            return result_type("png");
+        }
+        else if (magic == 0x49492A00 || magic == 0x4D4D002A)
+        {
+            return result_type("tiff");
+        }
+    }
+    if (size>=2)
+    {
+        unsigned int magic = ((data[0] << 8) | data[1]) & 0xffff;
+        if (magic == 0xffd8)
+        {
+            return result_type("jpeg");
+        }
+    }
+
+    return result_type();
+}
+
+image_reader* get_image_reader(char const* data, size_t size)
+{
+    boost::optional<std::string> type = type_from_bytes(data,size);
+    if (type)
+        return factory<image_reader,std::string,char const*,size_t>::instance().create_object(*type, data,size);
+    return 0;
 }
 
 image_reader* get_image_reader(std::string const& filename,std::string const& type)
 {
-    return ImageReaderFactory::instance().create_object(type,filename);
+    return factory<image_reader,std::string,std::string const&>::instance().create_object(type,filename);
 }
 
 image_reader* get_image_reader(std::string const& filename)
@@ -46,7 +73,7 @@ image_reader* get_image_reader(std::string const& filename)
     boost::optional<std::string> type = type_from_filename(filename);
     if (type)
     {
-        return ImageReaderFactory::instance().create_object(*type,filename);
+        return factory<image_reader,std::string,std::string const&>::instance().create_object(*type,filename);
     }
     return 0;
 }
diff --git a/src/jpeg_reader.cpp b/src/jpeg_reader.cpp
index 169db9a6b..c90f31df4 100644
--- a/src/jpeg_reader.cpp
+++ b/src/jpeg_reader.cpp
@@ -23,7 +23,6 @@
 // mapnik
 #include <mapnik/image_reader.hpp>
 #include <mapnik/color.hpp>
-#include <mapnik/noncopyable.hpp>
 
 // jpeg
 extern "C"
@@ -34,24 +33,29 @@ extern "C"
 // boost
 #include <boost/shared_ptr.hpp>
 #include <boost/scoped_array.hpp>
+#include <boost/iostreams/device/file_descriptor.hpp>
+#include <boost/iostreams/device/array.hpp>
+#include <boost/iostreams/stream.hpp>
 
 // std
 #include <cstdio>
 
 namespace mapnik
 {
+
+template <typename T>
 class jpeg_reader : public image_reader
 {
-    struct jpeg_file_guard
+public:
+    typedef T source_type;
+    typedef boost::iostreams::stream<source_type> input_stream;
+    const static unsigned BUF_SIZE = 4096;
+private:
+    struct jpeg_stream_wrapper
     {
-        jpeg_file_guard(FILE * fd)
-            : fd_(fd) {}
-
-        ~jpeg_file_guard()
-        {
-            if (fd_) fclose(fd_);
-        }
-        FILE * fd_;
+        jpeg_source_mgr manager;
+        input_stream * stream;
+        JOCTET buffer[BUF_SIZE];
     };
 
     struct jpeg_info_guard
@@ -67,11 +71,13 @@ class jpeg_reader : public image_reader
     };
 
 private:
-    std::string file_name_;
+    source_type source_;
+    input_stream stream_;
     unsigned width_;
     unsigned height_;
 public:
-    explicit jpeg_reader(std::string const& fileName);
+    explicit jpeg_reader(std::string const& file_name);
+    explicit jpeg_reader(char const* data, size_t size);
     ~jpeg_reader();
     unsigned width() const;
     unsigned height() const;
@@ -81,44 +87,135 @@ private:
     void init();
     static void on_error(j_common_ptr cinfo);
     static void on_error_message(j_common_ptr cinfo);
+    static void init_source(j_decompress_ptr cinfo);
+    static boolean fill_input_buffer(j_decompress_ptr cinfo);
+    static void skip(j_decompress_ptr cinfo, long count);
+    static void term(j_decompress_ptr cinfo);
+    static void attach_stream(j_decompress_ptr cinfo, input_stream* in);
 };
 
 namespace
 {
 image_reader* create_jpeg_reader(std::string const& file)
 {
-    return new jpeg_reader(file);
-}
-const bool registered = register_image_reader("jpeg",create_jpeg_reader);
+    return new jpeg_reader<boost::iostreams::file_descriptor_source>(file);
 }
 
-jpeg_reader::jpeg_reader(std::string const& fileName)
-    : file_name_(fileName),
+image_reader* create_jpeg_reader2(char const* data, size_t size)
+{
+    return new jpeg_reader<boost::iostreams::array_source>(data, size);
+}
+
+const bool registered  = register_image_reader("jpeg",create_jpeg_reader);
+const bool registered2 = register_image_reader("jpeg",create_jpeg_reader2);
+}
+
+// ctors
+template <typename T>
+jpeg_reader<T>::jpeg_reader(std::string const& file_name)
+    : source_(file_name,std::ios_base::in | std::ios_base::binary),
+      stream_(source_),
       width_(0),
       height_(0)
 {
+    if (!stream_) throw image_reader_exception("cannot open image file "+ file_name);
     init();
 }
 
-jpeg_reader::~jpeg_reader() {}
-
-void jpeg_reader::on_error(j_common_ptr cinfo)
+template <typename T>
+jpeg_reader<T>::jpeg_reader(char const* data, size_t size)
+    : source_(data, size),
+      stream_(source_),
+      width_(0),
+      height_(0)
+{
+    if (!stream_) throw image_reader_exception("cannot open image stream");
+    init();
+}
+
+// dtor
+template <typename T>
+jpeg_reader<T>::~jpeg_reader() {}
+
+// jpeg stream wrapper
+template <typename T>
+void jpeg_reader<T>::init_source (j_decompress_ptr cinfo)
+{
+    jpeg_stream_wrapper* wrap = reinterpret_cast<jpeg_stream_wrapper*>(cinfo->src);
+    wrap->stream->seekg(0,std::ios_base::beg);
+}
+
+template <typename T>
+boolean jpeg_reader<T>::fill_input_buffer (j_decompress_ptr cinfo)
+{
+    jpeg_stream_wrapper* wrap = reinterpret_cast<jpeg_stream_wrapper*>(cinfo->src);
+    wrap->stream->read(reinterpret_cast<char*>(&wrap->buffer[0]),BUF_SIZE);
+    std::streamsize size = wrap->stream->gcount();
+    wrap->manager.next_input_byte = wrap->buffer;
+    wrap->manager.bytes_in_buffer = BUF_SIZE;
+    return (size > 0) ? TRUE : FALSE;
+}
+
+template <typename T>
+void jpeg_reader<T>::skip(j_decompress_ptr cinfo, long count)
+{
+    if (count <= 0) return; //A zero or negative skip count should be treated as a no-op.
+    jpeg_stream_wrapper* wrap = reinterpret_cast<jpeg_stream_wrapper*>(cinfo->src);
+
+    if (wrap->manager.bytes_in_buffer > 0 && count < wrap->manager.bytes_in_buffer)
+    {
+        wrap->manager.bytes_in_buffer -= count;
+        wrap->manager.next_input_byte = &wrap->buffer[BUF_SIZE - wrap->manager.bytes_in_buffer];
+    }
+    else
+    {
+        wrap->stream->seekg(count, std::ios_base::cur);
+        // trigger buffer fill
+        wrap->manager.next_input_byte = 0;
+        wrap->manager.bytes_in_buffer = 0; //bytes_in_buffer may be zero on return.
+    }
+}
+
+template <typename T>
+void jpeg_reader<T>::term (j_decompress_ptr cinfo)
+{
+// no-op
+}
+
+template <typename T>
+void jpeg_reader<T>::attach_stream (j_decompress_ptr cinfo, input_stream* in)
+{
+    if (cinfo->src == 0)
+    {
+        cinfo->src = (struct jpeg_source_mgr *)
+            (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT, sizeof(jpeg_stream_wrapper));
+    }
+    jpeg_reader::jpeg_stream_wrapper * src = reinterpret_cast<jpeg_reader::jpeg_stream_wrapper*> (cinfo->src);
+    src->manager.init_source = init_source;
+    src->manager.fill_input_buffer = fill_input_buffer;
+    src->manager.skip_input_data = skip;
+    src->manager.resync_to_restart = jpeg_resync_to_restart;
+    src->manager.term_source = term;
+    src->manager.bytes_in_buffer = 0;
+    src->manager.next_input_byte = 0;
+    src->stream = in;
+}
+
+template <typename T>
+void jpeg_reader<T>::on_error(j_common_ptr cinfo)
 {
-    //(*cinfo->err->output_message)(cinfo);
-    //jpeg_destroy(cinfo);
     throw image_reader_exception("JPEG Reader: libjpeg could not read image");
 }
 
-void jpeg_reader::on_error_message(j_common_ptr cinfo)
+template <typename T>
+void jpeg_reader<T>::on_error_message(j_common_ptr cinfo)
 {
     // used to supress jpeg from printing to stderr
 }
 
-void jpeg_reader::init()
+template <typename T>
+void jpeg_reader<T>::init()
 {
-    FILE * fp = fopen(file_name_.c_str(),"rb");
-    if (!fp) throw image_reader_exception("JPEG Reader: cannot open image file " + file_name_);
-    jpeg_file_guard guard(fp);
     jpeg_decompress_struct cinfo;
     jpeg_info_guard iguard(&cinfo);
     jpeg_error_mgr jerr;
@@ -126,38 +223,42 @@ void jpeg_reader::init()
     jerr.error_exit = on_error;
     jerr.output_message = on_error_message;
     jpeg_create_decompress(&cinfo);
-    jpeg_stdio_src(&cinfo, fp);
+    attach_stream(&cinfo, &stream_);
     int ret = jpeg_read_header(&cinfo, TRUE);
-    if (ret != JPEG_HEADER_OK) throw image_reader_exception("JPEG Reader: failed to read header in " + file_name_);
+    if (ret != JPEG_HEADER_OK)
+        throw image_reader_exception("JPEG Reader: failed to read header");
     jpeg_start_decompress(&cinfo);
     width_ = cinfo.output_width;
     height_ = cinfo.output_height;
 
     if (cinfo.out_color_space == JCS_UNKNOWN)
     {
-        throw image_reader_exception("JPEG Reader: failed to read unknown color space in " + file_name_);
+        throw image_reader_exception("JPEG Reader: failed to read unknown color space");
     }
     if (cinfo.output_width == 0 || cinfo.output_height == 0)
     {
-        throw image_reader_exception("JPEG Reader: failed to read image size of " + file_name_);
+        throw image_reader_exception("JPEG Reader: failed to read image size of");
     }
 }
 
-unsigned jpeg_reader::width() const
+template <typename T>
+unsigned jpeg_reader<T>::width() const
 {
     return width_;
 }
 
-unsigned jpeg_reader::height() const
+template <typename T>
+unsigned jpeg_reader<T>::height() const
 {
     return height_;
 }
 
-void jpeg_reader::read(unsigned x0, unsigned y0, image_data_32& image)
+template <typename T>
+void jpeg_reader<T>::read(unsigned x0, unsigned y0, image_data_32& image)
 {
-    FILE * fp = fopen(file_name_.c_str(),"rb");
-    if (!fp) throw image_reader_exception("JPEG Reader: cannot open image file " + file_name_);
-    jpeg_file_guard guard(fp);
+    stream_.clear();
+    stream_.seekg(0, std::ios_base::beg);
+
     jpeg_decompress_struct cinfo;
     jpeg_info_guard iguard(&cinfo);
     jpeg_error_mgr jerr;
@@ -165,9 +266,9 @@ void jpeg_reader::read(unsigned x0, unsigned y0, image_data_32& image)
     jerr.error_exit = on_error;
     jerr.output_message = on_error_message;
     jpeg_create_decompress(&cinfo);
-    jpeg_stdio_src(&cinfo, fp);
+    attach_stream(&cinfo, &stream_);
     int ret = jpeg_read_header(&cinfo, TRUE);
-    if (ret != JPEG_HEADER_OK) throw image_reader_exception("JPEG Reader: failed to read header in " + file_name_);
+    if (ret != JPEG_HEADER_OK) throw image_reader_exception("JPEG Reader read(): failed to read header");
     jpeg_start_decompress(&cinfo);
     JSAMPARRAY buffer;
     int row_stride;
diff --git a/src/png_reader.cpp b/src/png_reader.cpp
index 324c33e7d..67a873f65 100644
--- a/src/png_reader.cpp
+++ b/src/png_reader.cpp
@@ -20,32 +20,29 @@
  *
  *****************************************************************************/
 
+// mapnik
 #include <mapnik/debug.hpp>
 #include <mapnik/image_reader.hpp>
-#include <mapnik/noncopyable.hpp>
 
 extern "C"
 {
 #include <png.h>
 }
-
+// boost
 #include <boost/scoped_array.hpp>
+#include <boost/iostreams/device/file.hpp>
+#include <boost/iostreams/device/file_descriptor.hpp>
+//#include <boost/iostreams/device/mapped_file.hpp>
+#include <boost/iostreams/stream.hpp>
 
 namespace mapnik
 {
+
+template <typename T>
 class png_reader : public image_reader
 {
-    struct png_file_guard
-    {
-        png_file_guard(FILE * fd)
-            : fd_(fd) {}
-
-        ~png_file_guard()
-        {
-            if (fd_) fclose(fd_);
-        }
-        FILE * fd_;
-    };
+    typedef T source_type;
+    typedef boost::iostreams::stream<source_type> ifstream;
 
     struct png_struct_guard
     {
@@ -62,13 +59,16 @@ class png_reader : public image_reader
     };
 
 private:
-    std::string fileName_;
+
+    source_type source_;
+    ifstream stream_;
     unsigned width_;
     unsigned height_;
     int bit_depth_;
     int color_type_;
 public:
-    explicit png_reader(std::string const& fileName);
+    explicit png_reader(std::string const& file_name);
+    explicit png_reader(char const* data, std::size_t size);
     ~png_reader();
     unsigned width() const;
     unsigned height() const;
@@ -76,28 +76,26 @@ public:
     void read(unsigned x,unsigned y,image_data_32& image);
 private:
     void init();
+    static void png_read_data(png_structp png_ptr, png_bytep data, png_size_t length);
 };
 
 namespace
 {
+
 image_reader* create_png_reader(std::string const& file)
 {
-    return new png_reader(file);
-}
-const bool registered = register_image_reader("png",create_png_reader);
+      return new png_reader<boost::iostreams::file_descriptor_source>(file);
 }
 
-png_reader::png_reader(std::string const& fileName)
-    : fileName_(fileName),
-      width_(0),
-      height_(0),
-      bit_depth_(0),
-      color_type_(0)
+image_reader* create_png_reader2(char const * data, std::size_t size)
 {
-    init();
+    return new png_reader<boost::iostreams::array_source>(data, size);
+}
+
+const bool registered = register_image_reader("png",create_png_reader);
+const bool registered2 = register_image_reader("png", create_png_reader2);
 }
 
-png_reader::~png_reader() {}
 
 void user_error_fn(png_structp png_ptr, png_const_charp error_msg)
 {
@@ -109,35 +107,64 @@ void user_warning_fn(png_structp png_ptr, png_const_charp warning_msg)
     MAPNIK_LOG_DEBUG(png_reader) << "libpng warning: '" << warning_msg << "'";
 }
 
-static void
-png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
+template <typename T>
+void png_reader<T>::png_read_data(png_structp png_ptr, png_bytep data, png_size_t length)
 {
-    png_size_t check;
-    check = (png_size_t)fread(data, (png_size_t)1, length,
-                              (FILE *)png_get_io_ptr(png_ptr));
-
-    if (check != length)
+    ifstream * fin = reinterpret_cast<ifstream*>(png_get_io_ptr(png_ptr));
+    fin->read(reinterpret_cast<char*>(data), length);
+    if (fin->gcount() != length)
     {
         png_error(png_ptr, "Read Error");
     }
 }
 
-void png_reader::init()
+template <typename T>
+png_reader<T>::png_reader(std::string const& file_name)
+    : source_(file_name,std::ios_base::in | std::ios_base::binary),
+      stream_(source_),
+      width_(0),
+      height_(0),
+      bit_depth_(0),
+      color_type_(0)
 {
-    FILE *fp=fopen(fileName_.c_str(),"rb");
-    if (!fp) throw image_reader_exception("cannot open image file "+fileName_);
-    png_file_guard guard(fp);
 
+    if (!stream_) throw image_reader_exception("cannot open image file "+ file_name);
+    init();
+}
+
+template <typename T>
+png_reader<T>::png_reader(char const* data, std::size_t size)
+    : source_(data,size),
+      stream_(source_),
+      width_(0),
+      height_(0),
+      bit_depth_(0),
+      color_type_(0)
+{
+
+    if (!stream_) throw image_reader_exception("cannot open image stream");
+    init();
+}
+
+
+template <typename T>
+png_reader<T>::~png_reader() {}
+
+
+template <typename T>
+void png_reader<T>::init()
+{
     png_byte header[8];
     memset(header,0,8);
-    if ( fread(header,1,8,fp) != 8)
+    stream_.read(reinterpret_cast<char*>(header),8);
+    if ( stream_.gcount() != 8)
     {
-        throw image_reader_exception("Could not read " + fileName_);
+        throw image_reader_exception("Could not read image");
     }
     int is_png=!png_sig_cmp(header,0,8);
     if (!is_png)
     {
-        throw image_reader_exception(fileName_ + " is not a png file");
+        throw image_reader_exception(" File or steam is not a png");
     }
     png_structp png_ptr = png_create_read_struct
         (PNG_LIBPNG_VER_STRING,0,0,0);
@@ -155,7 +182,7 @@ void png_reader::init()
     info_ptr = png_create_info_struct(png_ptr);
     if (!info_ptr) throw image_reader_exception("failed to create info_ptr");
 
-    png_set_read_fn(png_ptr, (png_voidp)fp, png_read_data);
+    png_set_read_fn(png_ptr, (png_voidp)&stream_, png_read_data);
 
     png_set_sig_bytes(png_ptr,8);
     png_read_info(png_ptr, info_ptr);
@@ -169,21 +196,23 @@ void png_reader::init()
     MAPNIK_LOG_DEBUG(png_reader) << "png_reader: bit_depth=" << bit_depth_ << ",color_type=" << color_type_;
 }
 
-unsigned png_reader::width() const
+template <typename T>
+unsigned png_reader<T>::width() const
 {
     return width_;
 }
 
-unsigned png_reader::height() const
+template <typename T>
+unsigned png_reader<T>::height() const
 {
     return height_;
 }
 
-void png_reader::read(unsigned x0, unsigned y0,image_data_32& image)
+template <typename T>
+void png_reader<T>::read(unsigned x0, unsigned y0,image_data_32& image)
 {
-    FILE *fp=fopen(fileName_.c_str(),"rb");
-    if (!fp) throw image_reader_exception("cannot open image file "+fileName_);
-    png_file_guard guard(fp);
+    stream_.clear();
+    stream_.seekg(0, std::ios_base::beg);
 
     png_structp png_ptr = png_create_read_struct
         (PNG_LIBPNG_VER_STRING,0,0,0);
@@ -201,7 +230,7 @@ void png_reader::read(unsigned x0, unsigned y0,image_data_32& image)
     info_ptr = png_create_info_struct(png_ptr);
     if (!info_ptr) throw image_reader_exception("failed to create info_ptr");
 
-    png_set_read_fn(png_ptr, (png_voidp)fp, png_read_data);
+    png_set_read_fn(png_ptr, (png_voidp)&stream_, png_read_data);
     png_read_info(png_ptr, info_ptr);
 
     if (color_type_ == PNG_COLOR_TYPE_PALETTE)