How do I change images to 1024 x 768 @ 72 DPI & keep their proportions accurate? ?

My MFA program application requires me to send 20 still images (of paintings) on CD-Rom format as my portfolio and requires the images be at 1024 x 768 @ 72 DPI. I have Photoshop (CS3) but am not very skilled with it; when i tried to alter the images to these proportions they end up looking skewed. How to I keep their proportions but re-size them to fit the school's requirements?How do I change images to 1024 x 768 @ 72 DPI %26amp; keep their proportions accurate? ?
download a program called irfanview from download.com

or go to a website called lifehacker.com, they have lots of programs that will help you do that.How do I change images to 1024 x 768 @ 72 DPI %26amp; keep their proportions accurate? ?
The problem is that you're trying to put it into specifics that aren't working. It's like trying to take a square and resize it into a rectangle. Not going to work. When you resize, make sure that you're keeping the ratio and just resize either the length or the height. I do that with a lot of pictures that I have to resize to 800 pixels on the long size. Choose the long side and resize to 1024. If the short side is 768 or less, you're fine. If it's greater, you'll need to resize the short size and keep your long size shorter than 1024. I know it's confusing.
If you are just taking one of the corners and dragging it to size. Hold down the ';shift'; key resize to the larger side, then resize the canvas.