I used a widescreen frame capture from Premiere and then brought that into Photoshop CS3 to use as a background for a composite. I did the compositing work on it, and PS shows the widescreen aspect ratio preview and it looks great.
However, I want to print this and use it for use in a DVD cover. I have already upsized it using the 110% resampling trick.
Before printing, what should I do to prevent the squishing, that is occuring because it is using square pixels in PS.