fix: Documentation (#731)

Author: marco-langer

doc/design/dynamic_image.rst

@@ -159,14 +159,14 @@ upside down:
 
 .. code-block:: cpp
 
-  #include <boost\gil\extension\io\jpeg_dynamic_io.hpp>
+  #include <boost\gil\extension\io\jpeg.hpp>
 
   template <typename Image>    // Could be rgb8_image_t or any_image<...>
   void save_180rot(const std::string& file_name)
   {
     Image img;
-    jpeg_read_image(file_name, img);
-    jpeg_write_view(file_name, rotated180_view(view(img)));
+    read_image(file_name, img, jpeg_tag());
+    write_view(file_name, rotated180_view(view(img)), jpeg_tag());
   }
 
 It can be instantiated with either a compile-time or a runtime image

doc/io.rst

@@ -172,6 +172,8 @@ provides access to the so-called backend.
 
 For instance::
 
+    typedef bmp_tag tag_t;
+
     typedef get_reader_backend< const std::string
                               , tag_t
                               >::type backend_t;
@@ -245,7 +247,7 @@ The following example shows this feature::
              , gray16_image_t
              , rgb8_image_t
              , rgba8_image_t
-             > my_img_types > runtime_image;
+             > runtime_image;
 
     read_image( filename
               , runtime_image
@@ -323,7 +325,7 @@ Writing an any_image<...> is supported. See the following example::
              , gray16_image_t
              , rgb8_image_t
              , rgba8_image_t
-             > my_img_types > runtime_image;
+             > runtime_image;
 
     // fill any_image