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.
XnView MP - XnView is a free software that allows you to view, resize and edit your images. It supports more than 500 different formats!
Google Photos - All your photos are backed up safely, organized and labeled automatically, so you can find them fast, and share them how you like.
digiKam - Professional Photo Management with the Power of Open Source
Flickr - image and video hosting website
FastStone Image Viewer - FastStone Image Viewer is a fast, stable, user-friendly image browser, converter and editor.