Originally posted by geoffpem i think dpi subject is ie:- 72 dpi per image is default on some cameras and is used univesaly for viewing and 200, 300, whatever dpi converted image size is used for printing depending on size of print and quality of print
No, when you view an image in a web browser 1 pixel in the image gets displayed in 1 pixel in your browser, assuming you haven't zoomed the browser view in or out and the web designer has either put the correct pixel dimensions in or not put them in at all.
The 'universally for viewing' myth comes about as it used to be believed that all monitors had 72 pixels (dots) per inch. Also the belief that DPI matter for web site - had a big argument with a chap at the camera club about that, withdrew as he looked about to have a heart attack.
When you view an image in an editor the relationship between pixels in the image and on the screen depends on how you choose to view the image.
The DPI doesn't necessarily get used for printing either - you can tell many print drivers to stretch or shrink an image to fit the paper size.
I have a feeling Word does use it to initially size an image in a document, but it's easy to resize by dragging the corners.
If you Google 'DPI Myth' you will find plenty of articles about this that explain (in slightly different ways) why DPI is meaningless except (maybe) when you print. The only place I know of where it really, really matters is scanning when it is vital to use the right figure. What that is depends on the scanner, what you are scanning and what the scan is going to be used for. I use 4,000 dpi when scanning 35mm negatives or slides with my Nikon scanner.