Specifically from a photo that was scanned and saved in jpeg format? I have a terminally ill family member whose wife wants a 4x6 photograph to be enlarged to a 16x20 poster. I worry about distortions due to excessive enlargement. The money is limited and Costco appears to have a great service for specialized photo requests but I'm uncertain that there any trained employees to help with the enlargement to be successful and have excellent quality considering the customer inputs the entire order through a computer and uploads photo from either memory card or from online photo sites no physical scanners that I know of so taking in the physical photo won't help. I want this to be perfect since it will be memorial picture, but with it being trying times I can't spend a great deal of money and wouldn't want to waste loads of with repetitive unsuccessful professional-grade posters.