I have several low resolution 160x120 images that I want to combine (with columns and rows) and print in 4R.
When I do a 4x4 i.e. 16 photos (640x480 pixels), the photolab couldn't print it because of cropping issues but I have other 640x480 shots (single photos) that were able to be printed. Why is that so? What is the best way to determine how many photos I can combine this way for optimum 4R printing?