A Guide to Sizing Images for Online Sharing

Optimize the resolution of an image to ensure efficient transmission

Save for Web prompt in Photoshop

When you post photos online, you do not need nearly as many pixels as you do for printing. This trend also goes for images that will only be viewed on-screen such as in a slideshow or presentation.

How to Make Pictures Smaller for Online Use

When you place your photos on the web or send them by email, the smaller you can get them, the better, to make the most efficient use of bandwidth and storage space. There are three things you can do to make your pictures smaller for sharing online:

  1. Crop: Change the dimensions of an image by removing superfluous material from the periphery of the image.
  2. Change pixel dimensions: Resample an image to remove unnecessary pixels.
  3. Use compression: Various alternative image formats offer file-size efficiency at the price of image precision.

Since pixels-per-inch and dots-per-inch are only relevant to print size and quality, for digital photos for the web, you need only look at pixel dimensions. Most 24-inch desktop monitors today offer a resolution of 1920 by 1080 pixels, so your images need not be larger than this for on-screen viewing. Laptops and older computers will have an even lower screen resolution, so keep that in mind as well. The smaller the pixel dimensions of an image, the smaller the file size will be.

  • When sharing photos online, 1200 by 800 pixels is a good average size to go with.
  • If you wish to reduce file size even further, reduce your images down to 800 by 600 or even 640 by 480.
  • If you're sure your recipients or website visitors won't mind waiting a little longer, you may want to go as large as 2000 pixels wide, but anything larger than that is going to be too large to see in the majority of computer monitors without scrolling or downscaling on the fly.

File compression is another way to make your photos smaller for online use. Most cameras and scanners save in the JPEG format and this format employs file compression to keep the file size down. It is a standard file format that any computer can read. JPEG compression can be applied at various levels, with image quality and file size having an inverse relationship. The higher the compression, the smaller the file, and the less quality it will have.