15 online photo editors!

Service	Flash/HTML	Max. size	Max. resolution	Cost	Layers	Effects	Killer feature
Flauntr	Flash	10MB	2850x1599	Free	No	Yes	Part of a larger suite of editing products. You can take your file to another tool without losing changes.
Fotoflexer	Flash	No limit	4500x4500	Free	Yes	Yes	Handles multiple layers with grace. Includes advanced features like curve tweaks and intelligent lassoing for free.
Lunapic	HTML	4MB	1330x1330	Free	No	Yes	Can run on machines without Flash installed. Really inventive special effects--especially reflective water that ripples.
Phixr	HTML	No limit	1440x1080	Free	No	Yes	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.
Phoenix	Flash	No limit	2800x2800	Free	Yes	Yes	Great layer masking, community support, and tutorials. Work from Phoenix can be sent to another editing tool in the Aviary Web suite.
Photoshop.com	Flash	10MB	6000x6000	Free	No	Yes	Editing features get previewed in real time. Also runs on Adobe's latest and greatest Flash technology.
Picnik free	Flash	16MB	4000x4000	Free	Yes	Yes	Default photo editor for Flickr, very slick interface.
Picnik premium	Flash	16MB	4000x4000	$24.95/year	Yes	Yes	Bigger uploads and more effects filters. App also remembers what you were doing the last time you were using it.
Picture2Life	HTML	5MB	1600x1600	Free	Yes	Yes	Can run on machines without Flash installed. Floating windows workspace, similar to desktop apps.
Pixenate	HTML	10MB	1600x1200	Free	No	Yes	Can run on machines without Flash installed. Tooth whitening tool perfects yellow smiles with two clicks.
Pixer.us	Flash	10MB	6000x6000	Free	No	Yes	Remembers the last photo you were working on and has a wide range of filters and effects.
Pixlr	Flash	No limit	2880x2880 (Flash 9 users) 4096x4096 (Flash 10 users)	Free	Yes	Yes	Feels a lot like a desktop application, complete with a workspace which you can rearrange and customize to your liking.
Snipshot	HTML	10MB	5000x5000	Free	No	Yes	Can run on machines without Flash installed. Can import the first page of a PDF file for editing.
Snipshot Pro	HTML	10MB	5000x5000	$7/month	No	Yes	Effects filters, face detection, support for RAW camera files.
Splashup	Flash	~6.25MB	1250x1250	Free	Yes	Yes	Really great handling of layers. Photoshop users will feel right at home with some of the user interface.