I'm in the prep stages of a new jacquard weaving. This one incorporates portraits, so the aspect ratio must be accurate. The piece was designed with a balanced weave (epi=ppi). I wove a test strip, and found that with these particular yarns the actual woven epi is 64 and ppi is 48, therefore the woven aspect ratio is .75.
So I went back to the original layered file with weaves applied as layer styles, resized it, flattened it, and saved it as a tif to send to the loom. It should look right now.