Absolutely not. We prefer you upload your file before it is enlarged. Not to say you cannot do this but to do so might result in a poorer quality print than you would have wanted. This is because when you enlarge a digital image, you are adding pixels that were never there. Our software will try to guess what those pixels will look like and the more guessing it has to do, the more pixelated the image becomes. The reason we prefer you not to do this yourself is so we can warn you if we think the file is too small for the size you selected.