diff --git a/source/pngu_impl.h b/source/pngu_impl.h
new file mode 100644
index 0000000..fb20a70
--- /dev/null
+++ b/source/pngu_impl.h
@@ -0,0 +1,42 @@
+#ifndef __PNGU_I__
+#define __PNGU_I__
+
+#include "png.h"
+
+// Constants
+#define PNGU_SOURCE_BUFFER			1
+#define PNGU_SOURCE_DEVICE			2
+
+// Prototypes of helper functions
+int pngu_info (IMGCTX ctx);
+int pngu_decode (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, PNGU_u32 stripAlpha);
+int pngu_decode_add_alpha (IMGCTX ctx, PNGU_u32 width, PNGU_u32 height, PNGU_u32 stripAlpha, int force32bit);
+void pngu_free_info (IMGCTX ctx);
+void pngu_read_data_from_buffer (png_structp png_ptr, png_bytep data, png_size_t length);
+void pngu_write_data_to_buffer (png_structp png_ptr, png_bytep data, png_size_t length);
+void pngu_flush_data_to_buffer (png_structp png_ptr);
+int pngu_clamp (int value, int min, int max);
+
+
+// PNGU Image context struct
+struct _IMGCTX
+{
+	int source;
+	void *buffer;
+	char *filename;
+	PNGU_u32 cursor;
+	PNGU_u32 buf_size; // buffer size
+
+	PNGU_u32 propRead;
+	PNGUPROP prop;
+
+	PNGU_u32 infoRead;
+	png_structp png_ptr;
+	png_infop info_ptr;
+	FILE *fd;
+	
+	png_bytep *row_pointers;
+	png_bytep img_data;
+};
+
+#endif