AlilG - FREE - Simple editor that looks a lot like Photoshop, but without as many tools and effects.
Aviary - FREE - Edit images, create mind-blowing effects, design logos, find colors, collaborate, and more. All you need is a web browser.
DrPic - FREE - Lots of features of popular photo editing tools - Gausian Blur, Autofix, Sharpen, Brush, Polaroid, Oil Paint, Crop, Brightness, Resize, More!
Flauntr - FREE - Flash - Part of a larger suite of editing products. You can take your file to another tool without losing changes. Maximum Resolution. = 2850x1599
FlipMyPhotos - FREE - Easy to use online photo editor - Has many common features of popular photo editing tools (such as cropping, rotating, red eye reduction, etc.)
Fotoflexr - FREE - Flash - Handles multiple layers with grace. Includes advanced features like curve tweaks and intelligent lassoing for free. Max. Res = 4500x4500
Lunapic - FREE - Can run on machines without Flash installed. Really inventive special effects--especially reflective water that ripples. Max. Res = 1440x1080
MyImager - FREE - odd interface where everything uses a dropdown menu which causes the page to reload when you make a change. The service only accepts GIFs and JPGs, and is free, but advertisement heavy.
Online-Image-Editor - FREE - Good for minor editing, and obviously directed at the social networking crowd since it has a tool named “Glitter Wizard.”
Phixr - FREE- Can run on machines without Flash installed. Does not save your photos on its servers for very long, so you can edit sensitive images and nobody will see them. Max Res = 1440x1080
Phoenix - FREE - FLASH - Great layer masking, community support, and tutorials. Work from Phoenix can be sent to another editing tool in the Aviary Web suite. Max Res = 2800x2800
Photoshop Online - FREE - FLASH - Editing features get previewed in real time. Also runs on Adobe's latest and greatest Flash technology. - Max Res = 6000x6000 [ Compare to: Adobe Photoshop CS4 - Full Version ]
PicJuice - FREE - Easily edit your photos: resize, crop, rotate, flip and adjust contrast and color levels.
PicResize - FREE - 2.0 Version - Easily resize photos
Picture2Life - FREE - Can run on machines without Flash installed. Floating windows workspace, similar to desktop apps. Max Res = 1600x1600
PikiPimp - FREE - Upload your photo and add bling.You can sell your ideas and put it on a t-shirt!
Pixastic - FREE - Javacript Editor - Emboss, Sepia Tone, Invert, Blur + other transform & adjustment tools
Pixenate - FREE - Can run on machines without Flash installed. Tooth whitening tool perfects yellow smiles with two clicks. Max Res = 1600x1200
Pixer.us - FREE - FLASH - Remembers the last photo you were working on and has a wide range of filters and effects. Max Res = 6000x6000
Pixlr - FREE - FLASH - Feels a lot like a desktop application, complete with a workspace which you can rearrange and customize to your liking. Max Res = 2880x2880
Pizap - FREE - FLASH - Free Gallery to Save and Share Your piZaps w/ Privacy Controls - Transfer on to products for sale
Snipshot - FREE - Can run on machines without Flash installed. Can import the first page of a PDF file for editing. Max Res = 5000x5000
Splashup - FREE - FLASH - Can run on machines without Flash installed. Can import the first page of a PDF file for editing. Max Res = 1250x1250
SumoPaint - FREE - FLASH - Create, edit and comment images online - ADVANCED Web Paint app with layer support - Layer effects, ink tool, Clone stamp, shape trails, gravity, magic wand, filters, gradient tool, zoom tool, curve tool, selection modify and more!
Webresizer - FREE - Crop & Resize Photos Online - Optimizes photos for web or email