Recently, I was asked about why I ask my clients to either provide 300 dpi graphics when they scan, or why I scan artwork at 300 dpi. As an experienced web graphics company we need to know we are handling top quality graphics. For instance, if you scan a poster at 72 dpi and get it to us that way, the image may be just fine for web usage, but we keep these graphics on file for future use by the client. Now the client needs a graphic print created and printed using some of the scanned posters previously given at 72 dpi, this will not do. Now you either need to find the graphic and rescan, or start making a graphic without the artwork.
We recommend 300 dpi so that no matter what the end product we are equipped with the best graphic for the job. Besides when we are handed a 300 dpi graphic and we personally compress and resize the graphic it will look sharper than a client handing us a 72 dpi scan and resizing. We want the best for our client!