Board Thread:Support Requests - Designing Your Wikia/@comment-840648-20160328002618/@comment-17725354-20160328015626

Personally, I use GIMP to create/edit backgrounds, images, and such. It is open source and free to download, but it takes some experimentation to get used to using all the tools.

I also know of an online editor called Pixlr, which doesn't require any downloads. Like GIMP, it is free to use but it doesn't have as many tools/options.

Finally, there's Photoshop, which requires a paid subscription. I have never used it so I don't know how it compares to the other two. If you're not looking for something long term, you might be able to get a free trial and use that.