FWIW: Here's a link to an excellent explanation of DPI, PPI, image resolution and the confusion many people have about it. The Myth of DPI Also from the same site: What Magazines / Printers Really Want The Arithmetic of DPI (You might…

I would question the value of creating a 300dpi image meant for a final output size of 8'x4'. Large images like that are usually viewed from several feet away and a such seldom benefit from the added resolution. To the contrary, they take longer…