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.
Mega - Secure File Storage and collaboration
Sprite Monkey - Small and fast but still full-featured sprite sheet editor.
Dropbox - Online Sync and File Sharing
ShoeBox - Free unlimited photo storage, so you can rediscover your photos anywhere. Available for iPhone, iPad, Android, Mac and PC.
MediaFire - MediaFire is the simple solution for uploading and downloading files on the internet.