ShoeBox - Free unlimited photo storage, so you can rediscover your photos anywhere. Available for iPhone, iPad, Android, Mac and PC.
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.
TexturePacker - Texture Packer is hands down the best sprite sheet generation tool on the market.
digiKam - Professional Photo Management with the Power of Open Source
Free Texture Packer - Free Texture Packer is an open source tool that allows you to pack multiple images into one atlas for you games or sites.
Flickr - image and video hosting website