How do I change the pixel size of an image?

Okay...so I'm obsessed with the new movie Avatar by James Cameron. I want to change by Buddy Icon on my AIM to this cool Google Image picture I found of Avatar. The first thing i did was save my picture. Then I went to settings on my AIM %26gt; clicked the Expressions tab %26gt; clicked the Browse link %26gt; and then selected my picture %26gt; and then clicked Open. But after I clicked Open, a pop-up appeared and said: ';Error: The height and width of the image must be not more than 64 pixels or less than 15 pixels. (IM-0703';



I figured out that the picture was 535 x 418 pixels, and that AIM Icons need to be 48 x 48 pixels.



How do I change 535 x 418 pixels to 48 x 48 pixels?!



(I have Microsoft '03, Dell....if that has anything to do with it...i have no idea!)How do I change the pixel size of an image?
You can do a search on Google.com and find hundreds of programs to resize images.



Here is a link to an online image resizer that will do a quick job for your one image. You will only enter the width of 48 and the height will be calculated for you.



http://www.picresize.com/