digiKam - Professional Photo Management with the Power of Open Source
Lively - Make GIF and short movies from your live photos.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Flip - A seamless way to capture looping videos on mobile 🎬
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.
GIF Brewery by Gfycat - Create stunning GIFs from videos & screen recording for free