Lightroom allows you to set the size of a photo in pixels when exporting the photo. Everybody has their own “recommendations”. Some says to make it 500 pixels wide, some say 250 pixels wide… How big do you want your photo to be at 72 dpi? So if you want a photo to be 4 inch wide then make the photo to be 4x72 = 288 pixels wide.

Wrong! What’s wrong with these “recommendations”? The assumption that the standard screen resolution is 72 dpi. Most of these people are Mac users. The standard Mac resolution for the screen is 72 dpi, but the standard Windows resolution is 96 dpi! Many Windows users have set their computer to use the large fonts which convert their desktop to 120 dpi. A few extremely “poor sighted” people will have a resolution of up to 196 dpi. The use of 72 dpi makes it easy to convert the fonts from pixels to points, because they’re the same.

Estimate the size of the photo you want to have on the web: 3 inch wide, then multiply by 96 for the vast majority of the people = 288 pixels wide.

  • The Windows users will see the photo as 3 inch wide.
  • The Mac users will see the photo as 4 inch wide.

Mac has a 10% market share. The stats for my website are Mac:25.3%, Windows 62.7% and Linux/Unix: 12%. Most Linux/Unix users follows the same 96 dpi as Microsoft Windows. Mac users are more numerous in the photography world than the “regular” world. It’s still Mac - 72 dpi: 25% vs the rest of the world - 96 dpi: 75%.

  • When you are using a web browser, you do not control the user settings.
  • This is one of the reasons that photographers and developers insist on using Flash. So they can control the output and what it will look like. Flash is a major inconvenience to the users and the buyers.