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Thanks a bunch, man.  Sorry if that was dumb.

To most people, this will be a mind-numbingly stupid question.  Say I'm making a game in 640x400 in AGS.  I'm doing the backgrounds in photoshop.  I start my new document and I put in my height and width, but what should I put in the resolution?  Is there a standard, or a "true" resolution that won't give me either a too large or too small version of 640x400 (or whatever resolution I'm aiming for)?  Hopefully you haven't bashed your keyboard with your forehead too hard and can write back a response.