Absolutely not. We prefer you upload you file before it was enlarged. Not to say you cannot do this but to do so might result in a poorer quality print then you would have wanted. This is because when you enlarge a digital image you are adding pixels which were never there. Your 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. In addition if your image is not resized we automatically resize all images ourselves using more advanced algorithms than even Photoshop uses. We resize it to an optimal resolution based on what is being printed. This means we will be able to produce a better enlargement then you probably could. Finally because of the way we enlarge files, enlarging your file before submitting it just increases the file size making it more difficult to upload.