Pixlr

Pixlr is an open source picture editing software. You can use the website editor, or you can download a simpler mobile version.

Different Versions of Pixlr
There are three different versions of Pixlr
 * 1) Advanced - The most similar to Adobe Photoshop.  This is a good version to play around with if you are considering purchasing photoshop and want to get used to the basics.
 * 2) Express - Express is used for putting filters or borders on your pictures as well as creating collages.
 * 3) Pixlr-o-matic - Adds interesting film effects to still photos.

Pixlr Advanced Hot Keys
note:  If you are using Pixlr Advanced on a mac, make sure you are pressing "control" and not "command" when you utilize hot keys.