Aviary is a great resource that I use constantly. I use the Falcon and Talon online image editors to grab images from the web and edit/crop/add effects to use with my blog and with lesson materials. There are browser extensions to use with the online apps and it's very powerful.
A while back, Aviary launched an add-on for mobile devices that allowed you to use Aviary within mobile apps. Yesterday they announced that Aviary is now available as a free, stand-alone mobile app for iOS and Android.
The Aviary mobile app is free and features an easy-to-use, intuitive interface with effects, stickers, color balance, crop and rotate, brightness, contrast, saturation, drawing, text, cosmetic tools and more. There are more effects available for purchase in effects packages ($0.99) and more effects and tools are being added.
This is a great mobile tool that can be used for photo editing and effects on iOS and Android devices by teachers, students, bloggers, and for personal use, greatly increasing the abilities of your device. I now have the ability to do more of my work on my mobile device using this app. I was using it last night to edit some photos that I'm using in a project and it was very easy to use.
Try it out for yourself:
Aviary Falcon - online image markup
Aviary Education - safe environment for Aviary for Students
Aviary for Facebook Released - image editing app right in Facebook
Aviary Photo Editor now available to Flickr users-replacing Picnik
PicMonkey - free online photo editing (from some of the same people who made Picnik)
Great, free Image editing sites and software
Two More Free Image Editing Resources