If you upload very large images to your website, your website will slow down when those images are viewed by your visitors.
- file dimensions (width and height, in pixels) and
- file size (Kilobytes KB or Megabytes MB)
Sizing your images to 1,280 px wide is a good target for many websites. However you might target wider monitors, depending on your audience.
Here are some statistics on minimum screen widths as at Jan 2017 (see w3schools.com for latest information):
- 1024px wide: 96%
- 128opx wide: 93%
- 1366px wide: 84%
- 1920px wide: 49%
- 2560px wide: 8%
So statistically, if you size your images to 1280 px wide, in 93% of cases the images will be large enough to fill your visitor’s browser. Any larger and the image will be squeezed down in width anyway. If you want to fill the browser width for 84% of visitors, 1,366px wide will get there. If you use 2,560px wide, you’ll be able to display on large iMac displays at full width.
For most websites, make sure your file is no wider than the width of your webpage.
If you are planning on displaying images in full screen mode (such as the wide image shown above), you might want to plan for your full size images to be 1,280px, 1,920px or even wider.