GIMP - GIMP is a multiplatform photo manipulation tool.
digiKam - Professional Photo Management with the Power of Open Source
Adobe Photoshop - Adobe Photoshop is a webtop application for editing images and photos online.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Capture One Pro - The professionals’ choice in RAW image editing software with support for more than 500 cameras. Get started with Capture One today with a 30-day free trial.
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.