ShortPixel Adaptive Images serves the exact image size that your visitors’ devices need. That has a lot of advantages, but the most important are:
- Your page will load faster because your visitors won’t have to download the original (and probably huge) images.
- You will get rid of a few warnings on PageSpeed Insights, GTmetrix and similar.
There are certain situations where you might not want to serve the exact image size, though. Before explaining them, please first take 5 minutes to understand how ShortPixel Adaptive Images works and how the credits are counted.
Now, the size breakpoints will make sure that if an image needs to be resized to two sizes that are very close, they both will be resized to the same larger size. That has two clear advantages:
- There will be less cache misses on CDN, especially if you have less visited pages. Remember that if an image has never been visited before (and therefore cached on our CDN), the first time it gets visited it will be redirected to the original image (Why are my images redirected from cdn.shortpixel.ai?).
- If you use your own CDN with SPAI, less credits will be spent. Notice that this is irrelevant in case you use the default CDN.
The downside of this option is that the images will not always be perfectly sized, but in most of the cases a bit bigger than their display size. Also, in very specific cases, you may experience some quality loss due to the browser resizing what’s already being resized by our plugin.
Smallest resolution: This is the smallest width the images will have when being resized by the plugin.
Rounding factor: This is what creates the size breakpoints. Every image size breakpoint will be X% bigger than the previous. For example, if your smallest resolution is 50px and your rounding factor is 10%, your images will be served in the following widths: 50px, 55px, 61px, 67px, 73px, 81px, and so on.