i still have an OLD copy of shareware FREEware thumbsplus- which even if you try to pay for it the company is gone-and after 30 days, it just has a screen you have to clik to get to the proggy.
not sure if it would work on XP, it was for 98, still works on Me.
as far as free viewer/editors go, it is VERY good. many useful functions. MANY. it's relatively small, if some people post intrest, i can put it on my slow server for download............
sometimes i would rather resize or adjust levels with photoshop, but for most things like rotate and crop, its fine, and it will resize, adjust levels, etc if you want