It's a simple task to rename files with the ".jpeg" extensions. But seems like the site should support uploading ".jpeg" files since they are usually the same thing.
I dont think so, jpg is a lossy format, meaning that anything converted to it gets a quality loss in favor of less size; thats a big no-no for game art, specially 2D. Just stick to PNG, people will shy away from most jpg and it wont reflect the real work. Renaming *anything else* to Jpg is a dumb move, the only exception i can see for the use of jpg is for humongeus textures where the quality loss doesnt matter much.
I'm sorry, my original post isn't clear. I'm not just talking about game art. The forums, & the site in general, allow uploading JPEG image files for whatever reason, so long as the file is named with the ".jpg" extensions. It does not accept files using the ".jpeg" extension. Even though ".jpeg" is usually just an alias or alternative of ".jpg". So in order to upload a JPEG screenshot attachment to the forum, I have to rename my ".jpeg" files.