[IT_Architect]

Well...I learned it was working as advertised, but I didn't like the behavior. It started after I installed Android and a moved a lot of app installs to my microSD. On the microSD, by default, any directory it finds media files in that isn't flagged ignore, it caches any known-type media files it finds. That is probably a good default-behavior choice, but it doesn't work for me anymore.
For me, it did few things, none of which were good.
1. When flipping through the viewer, I had at least hundreds of pictures that followed the normal ones.
2. In \Application Data\HTC\HTC Album\Cache on the phone it makes a huge data file, which doesn't shrink. I had to turn off Sense to get rid of the cache files.
3. It creates a huge \Storage Card\DCIM\.thumbnail directory on the storage card that shows the thumbnails for the cached pictures, even after you set it to ignore, because they are in the cache from before. I had to delete those too.

The thread I found the fix on is actually for the Leo, which outside of snapdragon and the capacitive screen, is a lot like the Rhodium with 6.5. It is the most useful thread for Sense + Windows Mobile 6.5 that I've found so far: [REF] *Leo Hints, Tips and Registry Tweaks* - Updated 27th January 2011. - xda-developers

I have a lot more free space on my phone now, and I will still be able to see pictures stored in other directories on the phone now, such as pictures taken by Android, My Pictures on the phone, and My Pictures on the microSD.

During this journey, I found a wonderful app to find the directories and files eating up space, TreeSize Mobile. It's free, and I like it better than the one I would have been happy to pay money for.