Hi Cyn, my DH suggests the following:
There is probably an app already on that computer that can do the job. Check for Microsoft Photo Editor. There are probably a lot of free Photo Editors out there, a quick Google search should yield a few decent apps.
To get the pictures just right, I would suggest the following:
Create a blank photo template in the photo app at the size you need to print (say 4x6)
Drag or copy the photo onto the blank photo and resize to fit onto the template. What out for different densities or dpi. Web photos tend to be 72dpi where actual photo files tend to be 300dpi or more.
Careful when resizing photos using the handles. You may need to hold down the shift or cntl key to maintain the aspect ratio.
Repeat for other photos using the same template. Save (using Save As) the resized photos as a different name if you may want them later.