Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Pixelmator - Pixelmator is an image-editing application for Mac and iPad.
Corel AfterShot Pro - Say hello to Corel AfterShot Pro 3, the world’s fastest photo workflow tool! Edit your photos up to 4x faster than Lightroom so you can spend more time behind the camera. Download a free 30-day trial today!
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
GIMP - GIMP is a multiplatform photo manipulation tool.