Maybe it will work but i'm not sure my members are so smart to understand this thing.
FYI, i'm using xengallery and it has profile cover. Every reuploaded image is working instantly without empty browser cache.
Reload page but still not working.
Feature request:
-About your resize option, i think it's better if we can drag the image and save it rather than auto resize and crop the image.
-Can you add thread cover as thread thumbnail like this addon Thumbnails by Waindigo ?