(please read if you are confused because you see no "open" button or icon to start this app):
Ever been annoyed by the fact that when you want to email your friends a photo you recently took there's no quick way to reduce it's size because you don't want to sent the whole 5-8-12 megapixels of 2-3-5 megabytes to them just to let them check out the awesome pizza you had for dinner? Well with this app you get a nice "Resize" entry in your "Share with" menu.
Open your photo gallery and instead of choosing "Share with" and then selecting eg. Gmail, you can now choose "Share with" and then Resize, after selecting your size you again get a chance to choose the app you wish to share your photo with, but this time the photo will be shrunk to the selected size. Nice and simple and the way it should have been built into Android from the start!