Website: New image uploading system

The old method using the imgur API has been replaced. This gets rid of all the bugs of that API and the uploading restrictions.

Any image uploaded to the site will be optimized depending on its purpose. For instance, avatars will be downscaled to 100*100px if bigger, textbox sprites to 67*70px and will get a color pallete, etc. Pictures that can be uploaded anonymously will be removed periodically, so remember to download the images generated with those.