Mac: Pixelmator, our favourite image editing software on the Mac, was updated today with a couple of cool features for El Capitan, including split screen support and a Photos extension.
Split Screen support works exactly as you'd think and you can now easily run Pixelmator in full screen mode side-by-side with another app. More intriguing is the new Photos extension, which allows you to reshape, retouch, and create effects directly in Apple Photos. It's a nice, seamless editing experience, and even though Photos isn't great, it's nice to have some solid editing capabilities in it now.
Pixelmator ($46.99) [Mac App Store]