FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
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.
digiKam - Professional Photo Management with the Power of Open Source
Photoscape - high quality photo editing software, that enables you to fix and enhance photos.
Adobe Photoshop Lightroom CC - Adobe Photoshop Lightroom CC is a commercial photo processor and image organizer.
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.