Some of the mappings use the same icons because I couldn't find anything to differentiate them. For example Severe Thunderstorms and Thunderstorms are mapped to the same icon. I also have a little issue with some icons not displaying in the exact expected location, but I think this is an issue with how Java handles fonts.
Anyway this is the visual representation of the mapping...
The Java file that defines this mapping as an Enum is available from GitHub. The HTML version is here.
..and finally a screenshot of jPhotoFrame with a three day weather forecast...
-i