Let's say you're teaching a web design or digital photography lesson. You've made all your plans, you're ready to go, but you have one problem - you didn't sign up early enough to use the computer lab that has Adobe Photoshop installed on the computers. There's still a lab available, but those computers are so old that they won't even run a current version of Photoshop.
So what do you do? Well you could reschedule, but do you have a plan B to be working on in the classroom? There is a plan B, and it can be used in that other computer lab. myImager.com is a website that allows you to upload and image, then edit it in a variety of ways. It's not as full featured as some of the more well known image editing programs out there, but in a pinch it'll do the basic stuff for you.
If you have an image already uploaded to a server but want to edit it a bit, you can always head over to FlamingText.com and use their photo service. This isn't FlamingText.com's key feature (as you may guess by it's simplicity). Rather, they have a very nice system for creating headers and banners that say whatever you want them to say - including choice of fonts, colors, and even (in some cases) animation.