How do I adjust the dpi for an image in Photoshop...I know this may be a dumb question, but I am very new to the program. Thank you....

If you are wanting to increase the dpi for printing the option for dpi comes up when you go to print. If you want to increase the image quality you can increase the pixles per inch under image/image size. the F.O.G.

What exactly are you trying to do? There are different ways to change the DPI for different needs.If you just want to increase/decrease the DPI, the go under image size, but make sure you have the reample image box checked, or you image dimensions will change. However I feel as if I should warn you that if you increase the DPI the image quality won't really improve. Photoshop interpolates when you increase the DPI. DD#3

For an image for web, or only for looking on a screen, the resolution is 72 dpi. When you scan an image, the higher the resolution, the more details you'll have. The filters you'll apply will have better results. It's common use to scan at, say, 600 dpi, work on the image, then go down to 300 dpi for printing. That resolution has been choosen because it's roughly 12 line per mm, which is the eye resolution. But there are cases where the output media is resolution fixed, as a screen, where it is 72 dpi. When you use an photo from a library, say a 30*45 cm @ 150 dpi, if you need the size of the photo to be smaller, don't resample and so the resulting resolution will be higher. You are keeping the details which are there. Last,if you have an image at 72 dpi, on push the resolution to, say, 150 dpi, the quality will stay the same. The file will only be bigger. You can't invent details...

A little bit more: the resolution of an image and the printing resolution of, say, an Epson printer are two different things. For the Epson, in fact, we'll speak of "diffusion" of ink droplets. So you don't need to have an image at 1400 dpi to print at 1400 dpi on an Epson. Just use a 300 dpi image, and print at the 720 diffusion, which is usually excellent... Otherwise the file size will be incredible...