I guess it depends on what exactly the resizing software is doing to a larger than 960 image. If it's compressing it and stripping out data I doubt it would look great blown back up, but in any case I think it simply creates and stores a 960 image anyway, so there wouldn't be a bigger full-size for it to display even if the size limit went up later.
I'm not techie though, so could very well be talking total rubbish :)