GIMP - GIMP is a multiplatform photo manipulation tool.
Darktable - darktable is an open source photography workflow application and raw developer.
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
Adobe Lightroom - Adobe Lightroom is a family of image organization and image manipulation software.
Krita - Krita is a professional FREE and open source painting program. It is made by artists that want to seaffordable art tools for everyone. Concept art. texture and matte painters, illustrations and comics.
Dark Room - A quick, powerful photo editor that gives you control