There are actually quite a few good cloud-based options for editing photos online, depending on just how sophisticated you need to be with your editing. If it's just cropping, adjusting brightness and contrast, etc, there are lots of great easy options. (The photo editor in ChromeOS is actually pretty good for the simple stuff) But if you want to get fancy, here's a few far more sophisticated options...
Photoshop Lightroom ==> Polarr
The pro version of Polarr is free for educators. Go to www.polarr.co/education and get free access to Version 3.
Illustrator ==> Gravit
iMovie, Premiere, Final Cut, WMM ==> Wevideo
Also available on Android for mobile video editing
Add loops, real instruments, pre-recorded tracks, etc. Best feature is the ability to collaborate with others on a composition. Also works on mobile via the browser.
GarageBand ==> SoundTrap, AudioTool, AudioSauna
Web and Media >
Rich Media Production in the Cloud
Google Apps prove that you can have amazing office-style productivity software with just a web browser, but what about rich media production? If digital media is your thing, can you really create sophisticated music, video, photography and desktop publishing using nothing but a browser? The answer is yes! This session will introduce you to some of the amazing options for digital media production in the cloud. Bring a Chromebook or computer. This session is not really suitable for iPads.
Traditionally, most "pro-apps" have come from either the Adobe Creative Suite or Apple's professional tools. For many schools, especially those who have gone with Chromebooks, one of the challenges has been how to find workable substitutes for those more sophisticated applications. Things have improved a lot in this area over the past year or so, and the options for getting close to "pro" level functionality in your browser is not unrealistic. While most cloud based substitutes don't do everything that their more powerful counterparts do, they will usually be a credible alternative for doing 90% of the tasks that 90% of people need.