IResizer is a content-aware image resizing tool, which allows you to resize an image while preserving its most important parts. So if you have a photo where two people are some distance apart, for instance, you can reduce the space between them, without actually resizing the people themselves.
How does this work? The key with this kind of task is to tell iResizer which parts of the photo mustn't be rescaled. To do this, you just choose the green marker and draw over each of them, before clicking Resize and choosing the new image size. And that's it - iResizer will create your new and improved image in just a few seconds.
The program can also resize an image to remove some objects entirely, though. If you'd like to remove a particular person from a photo, say, just paint over them using the red marker, click Resize, and they'll disappear. And it's just as easy to get rid of stray animals, cars or other random objects which might be spoiling your composition.
The results can vary, as you'd expect with this kind of tool. Sometimes they're great, sometimes they're fine as long as you don't look closely, occasionally they're dreadful - it all depends on the source material.
The best part of iResizer is that it's very easy to use, though, and so it won't take long to find out how the program works for you. Whether it's good enough to justify the purchase price is another matter, but it's certainly worth taking the trial for a spin.