Picnik
With Picnik you can grab photos from your Flickr, Photobucket or Facebook account easily. Picnik includes advanced controls and effects in addition to basic options like cropping and re-sizing. A premium version is also available with more features for a little over $2 per month.
Photoshop
Adobe offers a free, online version of Photoshop with scaled down features that include those needed for basic photo editing. You can crop and re-size, apply basic touch ups, work with color, or edit the photo by adjusting the sharpness, focus and more.
Phoenix (from Aviary)
Aviary provides a suite of related tools, including an image editor named Phoenix. Phoenix includes basic and advanced editing tools and features. The interface is easy to use and resembles that of a stripped down version of Photoshop.
FotoFlexer
With FotoFlexer you can get photos directly from your Flickr, Photobucket or Facebook account. It allows you to re-touch photos, create various effects, work with shapes and text, and more, including some advanced features.
Pixlr
Pixlr offers Pixlr express for basic editing like cropping and re-sizing, adjustments, and photo effects. The full version includes a lot more functionality that allows you to create an item from scratch or edit an existing photo. The full version works similar to Photoshop or GIMP with a lot of different tools that can be used.
Splashup
Splashup provides a nice interface and a number of tools and features. You can start from scracth, upload a photo from your computer, enter a URL, or get a photo from Flickr, Facebook and others. Splashup offers a surprising number of options for a free online image editor.
Pixenate
Get started with Pixenate by uploading a photo, entering a URL, or get one from your favorite photo sharing website. It includes basic editing features like cropping and re-sizing, brightness adjustments, and drawing lines on photos.
Picture2Life
With Picture2Life you can perform basic edits, create collages, and share your photos. The editing features are very limited.
Dr. Pic
Dr. Pic allows you to get started by uploading an image or entering a URL. It includes basic functionality like cropping and re-sizing, brightness and contrast adjustments, sharpen, adding text, and a little more.
Lunapic
Lunapic is a feature-rich online image editor. You can work with existing photos or create new images. There are tons of effects to choose from, and many adjustments that can be made, plus drawing tools, anitmation, and more.
Other Options:
Phixr
You can start using Phixr by uploading a photo from your computer or by entering the URL of an image, or pull it from a photo sharing site. You can do basic things like crop or re-size, or use the other options like red eye removal, camera and lense effects, blur, and more.
Free Online Photo Editor
Get started by uploading a photo or entering the URL of a photo. Free Online Photo Editor includes basic functionality like cropping, re-sizing, brightness/contrast adjustments, working with text, and a number of effects.
PiZap
PiZap helps you to have some fun with your photos by adding speech bubbles, cutout faces, effects and more.
FlauntR
With FlauntR you’ll need to register as a user before editing photos. It includes fetaures like one-click effects and a profile image creator for over 30 social networks.
Pho.to
With Pho.to you will upload a photo from your computer or enter a URL for the photo. It offers options like cropping and re-sizing, color enhancement, and several artistic effects. You can also automatically create a caricature from a photo.
OnlinePhotoTool.com
With Online Photo Tool you can do basic editing, and images can be saved if you register. Functionality includes re-size, crop, add text, sharpen, rotate, flip, colour balance, saturation, levels, and more.
MyImager
MyImager allows you to work with an existing photo via upload or a URL. Additionally, you can create a new image and work with the tools that are available, including a number of adjustments and effects, drawing tools, and more.
Pixer.us
Pixer.us allows you to upload a photo from your computer, and perform basic editing and touch ups. You can crop and re-size, plus adjust things like brightness and contrast, saturation, sharpness and more.
BeFunky
BeFunky includes 147 effects that can be done with one click. In addition to the one-click effects you can perform basic tasks like cropping and re-sizing. A premium account is available for $9.95 per month that allows for priority processing, photo storage and more.
Photo505
With Photo505 you can upload a photo and choose from a number of pre-made effects and filters to apply to your photo.
BigHugeLabs
With BigHugeLabs you can quickly create things like CD covers, pop art posters, magazine covers, billboards and more using your own photos.
Poladroid
Poladroid allows you to turn your photos into polaroid-style photos. You must download the Poladroid app before working with any photos.
Pixisnap
With Pixisnap you can create mosaics or polaroid tiles out of your images.
Photovisi
Photovisi helps you to make attractive collages from your photos.
Image Chef
Image Chef includes a few different types of tools. You can use the sketchpad to create your own work, or you can create word mosaics, photo frames and more.
72photos
72Photos allows you to do basic edits and store your photos online. A free account includes 200 MB of disk space and 10GB of bandwidth, or the pro account is available for $14.95 per year.
FixPicture
With Fix Picture you can do basic editing like cropping and re-sizing. Effects are also available for focus, contrast, sharpness, and more.
PicTreat
Pic Treat is a free tool that automatically retouches photos, including skin smoothing and red-eye removal.
AnyMaking
AnyMaking includes basic functionality like cropping, re-sizing, drop shadows and refelections. It also makes it easy to add fun effects to photos, like the retro comic effect, cartoon effect, wanted poster, and more.
WriteOnIt
Write On It makes it easy to create photomontages, cards, magzine covers, and more. Upload your photo and create your own effects on the photo.
