GIMP - GIMP is a multiplatform photo manipulation tool.
ACDSee - ACDSee is an image viewer that uses very little system resources, and it has a small, sleek size that won't take up much space on your system.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Pixlr - Pixlr® makes it easy to transform everyday images into stunning works of art.
Polarr - MacOS, Windows, iOS, Android and online photo editing tools & free photo editors.