I would use a paper application tape.
I tried a piece of the medium tack we have in stock on some sample lettering and it seemed to do ok. I would have thought it would pull the graphic off the wall.
The medium tack I tried on the sample lettering worked when the fabric wasn't printed. I then tried the same tape on the letters printed and it did not adhere. I may have to go to a heavier tack. Do you recall if you use a medium tack or heavy tack?