I'm familiar with both GIMP and Photoshop photo editors which are not available for the Chromebook, so I have been looking for something that would work for students at home. One of the coolest I have found is PIXLR. It is a cloud-based set of image tools and utilities, including a number of photo editors. The activities range from simple to advanced photo editing. I found these tutorials on the web, but will try to create a few myself in the next few weeks.