Another thing I would reccomend is to make sure your image isn't a super large resolution, because if you only resize it via HTML (as shown above), it will still require the entire image to be loaded, even though it may look smaller. I would advise resizing it in a program like Photoshop (or any similar photo editor), and make the image the exact size you would like to use for the application you are using it for.
A nice web based Photoshop alternative is called Pixlr (
http://apps.pixlr.com/editor/). This will allow you to resize the image to the dimensions you are wanting.