Aviary - A completely free online suite of powerful creative tools for artists of any genre from graphic design to sound editing.
BeFunky - Do amazing things with your photos! Free with no registration required!
Big Huge Labs - Do fun things with your photos! Make a motivational poster, a puzzle, magazine cover, and much more!
Bubblesnaps - Let your pictures do the talking! Add speech bubbles with captions to your photos.
Dumpr - Choose from 21 cool effects like museumr (show your photo as if displayed in a museum), lego-ize (your photo created from legos), or sketch artist (your photo being sketched by an artist).
FotoCrib - Create montages, add 3D effects, create rounded corners and much more!
FotoFlexer - A free online image editor that gives you tons of effects and options for creating great works of art from any photo.
FunPhotoBox - Create funny photo effects and GIF animations! Over 100 professionally designed effects.
GotBrainy - Upload a photo, then add a sentence, caption or definition to describe the photo. Great for vocab!
Iaza - No frills photo editor, but capable of doing so many things! Conversion, enhancements, adjustments, effects, borders, animations, and many many more!
ImageChef - Do amazing things with your photos and share them with your friends. Tons of cool effects!
LoonaPix - Lots of really cool effects to do with your photos! Place it on a billboard next to Harry Potter, or on a hot air balloon, or on a wanted poster, or on a dollar bill, at the bottom of a swimming pool, etc.
MakeRetro - Retro your photos easily using one of these 6 cool effects.
Muzy - Arrange your photos into a beautiful collage, combine your photos with text or collage your photos into a cool shape!
Pho.to - Add cool enhancements and fun effects to your photos!
PhotoFunia - Over 250 different effects and other cool things to do to your photos!
Photovisi - A free and easy-to-use photo collage maker.
Photo2Text - Convert your photograph into ASCII art (your photo comprised totally of text)!
Picascii - Another site to convert your photos into ASCII art.
PicMonkey - Awesome and fun photo editor! Holiday effects are a cool feature. Some enhancements are only available to paid subscribers, but the free options are more than enough to keep you satisfied! Some of the free effects include blemish fix, zombify, sepia, bokeh, posterize, lip tint, weight loss and more!
Pixenate - Simple photo editor with crop, rotate, flip, enhance, smooth, red-eye, teeth whitener, and doodler.
Pixlr - A suite of cloud-based image tools and utilities, with features found similar to those in Photoshop.
Speaking Image - Create, collaborate and share images with interactive notes.
Splashup - A powerful editing tool and photo manager but very easy to use!
SumoPaint - A full-featured photo editing/painting application, which totes itself as the "web's best image editor" and "the finest painter software online", SumoPaint is a collection of the next-generation of tools and services designed to make the world more creative.
Thumba - A drag-and-drop image editor with tons of features. Much easier to use than Photoshop!
Tuxpi - A free photo editor with 58 different editing tools.
Wet Floor Maker - Turn your photos into cool reflecting images.