I know, I know... I promised it long time ago but I decided to take some time off from coding, not even mentioning nerve-wracking Magento(; But I'm back in business now so here is your short guide on how to crop your images. You can use it for almost everything but it's great for designs with square (ish) products images.
There are quite few ways to optimise and speed up Magento. If you run a Google search you'll get different solutions from minifying js to some nice server settings. There is one thing though I couldn't see being mentioned anywhere - built-in image caching system.