fixed subimage logic

include/amscppimglib4/amscppimglib4.hpp

@@ -115,6 +115,12 @@ namespace ams
     int read_image(const char *fname, amsimage* image);
     int write_image(const char *fname, amsimage* image);
 
+    //functions to manipulate png compressed images in memory
+    int image_to_pngbytes(amsimage *image, unsigned char *pngbytes, long bytes_available, long *bytes_written);
+    long image_to_pngbytes_bytesneeded(amsimage *image);
+    int pngbytes_to_image(unsigned char *pngbytes, long bufferlength, amsimage *image);
+    
+
     class amsbitplane
     {
         public:
@@ -216,8 +222,6 @@ namespace ams
     };
 
 
-
-
 }; //end namespace ams
 
 #include <amscppimglib4/amscppimglib4_tests.hpp>