DPI Doesn’t Matter
OK, so I should probably clarify the rather misleading title with “for web use”.
I frequently have to ask for photos or images at a certain size, and because I’m one of those web types I use pixels as my measurement of choice. Invariably one of the first questions I get asked is “What DPI?”. When I explain that the DPI doesn’t matter for the web I get looked at like I’m from another planet. So for those that are already thinking I’m a little green man, let me show you an example.
Here we have a 500x200px photo at 72 DPI:
Here we have the same image, this time at 300 DPI:
And finally, here we have the image again, now at 1 DPI:
All three are identical in file size, at around 40Kb and all are exactly the same quality. Feel free to download and check them in Fireworks, or your image editor of choice, to make sure I’m not lying to you.
DPI, standing for Dots Per Inch, clearly has no affect on web images since an inch isn’t a unit of measurement that has any bearing on-screen.
A 20x20px image is a 20x20px image at 1 DPI or at a 1000 DPI.
- August 2010
- July 2010