Dpi issues with the s40

DPI in the EXIF data is totally spurious. Are you using a printer which only prints 300 DPI ? Any recent printer is at least double that. You have DOTs per inch, and Pixels per inch. Which are different things. DOTs per inch is a printing term. In offset printing, there are no shades of grey so you use a half-tone screen which produces dots of different sizes. The finest screen is ... 300 DPI. Depsite a lot of people bring "300" into discussions it's pretty meaningless. Inkjet printers don't rely on the same kind of dots, and they go up into 5000 DPI range. Printers print more dots than your picture has pixels. All printers will interpolate the Pixels you give them into the right number of DOTS to fit on the paper. It is very rate that spreading your image over more Pixels in photoshop will do better than the printing hardware. If you really need to interpolate the image out to more pixels look at Qimage (and have a read of http://www.ddisoftware.com/qimage/quality/ too).

Do not be too bummed out. The DPI reported in the EXIF data does not mean all that much. What does matter is the total number of horizontal and vertical pixels in an image and how this relates to the output size. For instance, your camera is capable of producing a 2304 by 1728 pixel image. This works out to about 220 DPI when printing an 8 by 10 inch picture. If you look at this the other way around, image editors will indicate an image size of 32 by 24 inches for an image taken by your camera (2304/72 and 1728/72). It is doubtful you will print at this size. Image software will take advantage of the full resolution when printing an 8 by 10, or 11 by 14.