I've featured a number of online photo tweaking websites, but RSIZR is by far one of the coolest. Free to use, no registration, RSIZR is designed to perform a number of innovative tricks. At its simplest, it can change the shape or "rezise" your photos to fit the format you need. When you crop a photo, you tend to end up with an odd-ly shaped result, something either too square or too horizontal. When you take out a section of a photo with RSIZR it can stretch the edited section into the same format as the original with little image loss. It's hard to believe, but the magic is the result of a new algorithmic process called "seam-carving" that can quickly analyze a photo a find horizontal or vertical lines of pixels that are both safe to remove or safe to duplicate, and so can either shrink or expand a photo. But wait, there's more. This same process also makes it easy to completey "erase" a person or object in a photo. You simply use a selection tool to hi-light an area and the photo will create seams around it, remove it, and then join the photo back together.