"ICONIMAGE" is a binary struct defined by Microsoft for saving an single icon (See this article in msdn). This UDF is basically for icon management, it takes ICONIMAGE as an binary intermediary to handle icons. With this UDF, you can:
Load, save, and convert icon in any size, any format, even can handle Vista PNG icon under Windows XP. Supported icon format: standard or PNG .ico, .png file, or other image files (.bmp/.jpg etc). Source and destination can be files or binary data.