vickyva, you resize the images on your computer using software. If you have photoshop or photopaint, look for the "resample" option. If you do not have either of these programs, there are free programs out there. Microsoft has one that works on Windows XP. It can be found here: http://www.microsoft.com/windowsxp/Downloads/powertoys/Xppowertoys.mspx
If you scroll down, you'll see a link on the right-hand side for ImageResizer. This is a very simple tool to convert one or a batch of photos to one of three sizes (basically, a small, medium, or large). I've used it and it works well, and takes up very little memory on your PC.
If you are running Vista, VSO Image Resizer is getting very good reviews, and is free. You can download here:
http://www.download.com/VSO-Image-Resizer/3000-2193_4-10529104.html?tag=mncol&cdlPid=10866964
If you need to actually crop the pictures first, to make them all the same shape (and you don't have PhotoShop or PhotoPaint), you can use Windows Paint or Windows Photo Gallery.