XP will definitely re-size images; right click on the image in Windows Explorer, "Resize Pictures" and select "Small", "Medium", "Large" or "Hand Held".
"Small" (640 x 480) is the preferred size for PPRuNe.
I am advised Visa will do the same thing.
My personal preference is XP, Office 2007, Mozilla Firefox browser and Irfanview for image management.