Photoshop diehards might scoff at Pixlr Editor, but it gets the job done for basic to intermediate drawing and image editing. Pixlr comes with various brushes and effects, and it supports layers and layer masks. You can even save and load .PSD files if you’re coming from Photoshop. Though Pixlr doesn’t work completely offline, once you’ve opened it in your browser, the app becomes fully functional without a connection. In Chrome, consider installing the Edit in Pixlr extension, which lets you right-click and send images directly to the app.