I'm looking for free windows software for photo morphing and/or distortion.
As people keep upvoting the existing suggestions, I am temporarily putting this at the top in bold: As far as I can tell, neither paint.net nor the recommended gimp packages offer what I am looking for, but feel to correct me if I missed something.
There are plenty of good morphing programs one can buy e.g. Adobe AfterEffects, Morpheus, AngelMorph, but I need a free one. Well done distortion is much more important than morphing, but the two often go together for obvious reasons. I include morphing software in my question because morphing software tends to also do distortion secondarily, even if it primarily advertises itself as morphing software.
My apologies as apparently I wasn't clear, I thought by pairing the term distortion with morphing it would be clear that I meant the sort of free form distortion that is also used in morphing software. By distortion and morphing I do not mean a handful of specific canned distortions (e.g. barrel distortion), I mean distortion of the sort that usually goes hand in hand with morphing, i.e. extremely free form distortion. In morphing one transitions a picture of a tiger into a cow which involves lots of warping. Hence morphing software usually also allows free form distortion of images. The sort of free form distortion usually available in morphing software is what I am after. There are many algorithms that can be used to smooth and interpolate such warping from key points or key segments the user moves, and they will obviously vary in quality.