Sent to you by David Andrew via Google Reader:
Cropp is new online tool that will intelligently crop and/or resize your images in the browser without requiring any software. You can use the tool to crop a single picture or upload multiple images (max 5) and it will crop /resize them all to the desired sizes in a batch.
This is obviously a crowded field – search for "crop resize images" in Google and you'll find dozens of similar web apps that do cropping and much more – but there are few unique features in Cropp that you'll probably like.
One, Cropp is probably the only online app that does many-to-many cropping – you can upload multiple pictures, select multiple outputs sizes and it will provide you all the cropped versions in a downloadable zip file.
The other advantage is that Cropp algorithms will automatically try to preserve the most interesting parts of a picture in the cropped version (handy when you are trying to create small thumbnails). And if you aren't happy with the final output, you can always adjust the crop marquee manually to get the desired result.
See some more useful websites.