Darktable - darktable is an open source photography workflow application and raw developer.
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 Lightroom - Adobe Lightroom is a family of image organization and image manipulation software.
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Dark Room - A quick, powerful photo editor that gives you control
Fotor - Fotor is an all in one visual platform. It includes photo editor, collage maker, and graphic designer. You are free to make a visual look more beautiful.