Although we cant all be photo image editing experts, tools like this can definitely help you come very close. Picnik provides a clean and easy user interface that will get you started on tweaking your favorite images in no time. With an abundant set of Fonts, special effects and other advanced settings, this tool is a must use. The service is offered in both free and premium flavors. It also provides a decent API for developers to integrate certain features in their own applications also with some good tutorials.

You can also check out a Firefox plug-in on https://addons.mozilla.org/en-US/firefox/addon/4889