Thread:Honk111/@comment-3528596-20151109012828/@comment-104549-20151109220633

In Paint, if you use the Select tool to select just the portion of the image that actually depicts the character, the "Crop" option (just to the right of the Select option) becomes available. Click and save.

If you go to an image you've uploaded (like either of the links above) and scroll down to the info, click "File History", and the bottom of the new tab (just above "Read more") will be an option to "Upload a new version of this file". You can use that to upload the cropped version, even if it has the same file path as the original, once the new version is saved on your hard drive.