Resizing images online is not a rare find on the internet today - many sites offer this functionality. Last site I checked out was Mypictr, a site that offers you quick Creation of avatars you can use on social networks. Now if you have some kind of image you need to resize quickly, quickthumbnail is your friend. Not only will it resize your images to a fixed size, you can resize using percentages, using a slider bar, choose fixed px sizes to resize to or choose anyone of these or, choose from standard sizes which feature monitor sizes as well as avatar sizes.
Impressive.