www.shrinkpictures.com is a great tool.
I've been using irfanview (free small quick image editor) for about 12 years:
http://www.irfanview.com/
Resize the image and save it as a gif works about 99.8% of the time!
Using non alpha numeric characters in usernames is usually discouraged. The forum will support it for the most part, but it can potentially cause issues with things like chat, page creation tool, etc.