Cam: The reason DPI is meaningless on a monitor is that DPI is a standard output. Taken to its simplest form, it means the number of dots that lined up one after another measures one inch of output. This works on output devices like printers. No matter the brand or size of the printer (whether it's a little 4"x6" inkjet photo printer or a HP designjet capable of 53" wide output) if you print 72 pixels in a straight line at 72dpi, you get a 1" long line [within mechanical tolerance of course]. Now, think of a monitor. You've got Joe sitting there with a nice 800x600 screen on a 19" monitor. He has 72 pixels lined up across his screen at 72dpi and miracle of miracles, it measures 1". Now Joe doesn't touch the image, but changes his screen resolution to 1280x1024. Now, his 72 pixel line in the 72dpi image that he hasn't touched measures only about 0.6" in length. Joe puts the desktop res back to 800x600, but changes from the 19" monitor to a 17" monitor or to a 21" monitor. The length of the line changes proportionally with the size of the monitor. In fact, the line length will change with every monitor and screen resolution change. So, in essence, since there is no one "standard monitor size and screen resolution" you can't apply a standard like DPI to it. File resolution alone is independent of DPI; DPI is a standard for output. The reason an image gets larger when you change its DPI in a program like Photoshop is because you are telling it to resample (enlarge or decrease) relative to the old DPI. So, if you have a 1000x1000 image at 100DPI and you tell it to go to 200DPI with resampling, Photoshop says "The user wants to print the image the same size as before, but they want to do it with twice as many pixels making up one inch, so I must increase the resolution by twice as much" and the image becomes 2000x2000. Here's a good visual, load an image in photoshop. Go to "Image Size", uncheck "Resample Image" and then change the DPI. Notice how the resolution stays the same, but as you increase the DPI the printed size goes down, and as you decrease it the size goes up - even though resolution remained the same. Next two images are examples of what I mean. -=>Donald