Flickr - image and video hosting website
TexturePacker - Texture Packer is hands down the best sprite sheet generation tool on the market.
Imgur - Imgur is a free and simple image hosting service with image editing feature. Signup is optional.
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.
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.
Sprite Sheet Packer - Sprite Sheet Packer is online that you can easily use to pack sprite sheets, including data formats for CSS, LESS, and Phaser.