SUMO Paint is a free web based (online) image editor. What’s really nice about this service is that it has some of the features that you would see in image editor like GIMP or Photoshop (that you need to install on your computer). SUMO Paint can do many things like transform an image, it has support for multiple layers and many other features like a smudge tool, blur tool, and symmetry tool. This is a great tool to have in your toolbox if you use maps in your humanities classes. You can edit them online and them download them. SUMO Paint also has a community you can post your images to for others to see and comment (but you can not directly save the image to services like Facebook or Flickr, you would need to download them to your computer first).
If you want to explore the tool before creating an account, you can by visiting the link below: