If your site feels a little slower in the first minutes after turning on Image Optimization, that's expected and temporary. You're seeing the cache warm up. Once it's warm, your pages are lighter and faster than before. Here's what's happening and how to confirm it settles.<\/p>\n\n\n\n
The first time each image is requested after you enable optimization (or after a purge), we build the optimized version on the fly and then cache it on the CDN. That very first build adds a moment of work, so the earliest views of each image are slightly slower. Every visit after that is served the cached, optimized copy instantly.<\/p>\n\n\n\n
So the slowdown you might notice is the cache warming up<\/strong>, and it's brief. It clears itself as pages are visited over the following minutes.<\/p>\n\n\n\n Once cached, optimized images are significantly smaller than the originals, so pages transfer less data and load faster, especially on mobile and slower connections. That's the steady state.<\/p>\n\n\n\n Note: On a small number of images that are already tiny or very simple (like a flat-color logo), the optimized version can come out a similar size to the original. Your overall pages are still lighter. If one specific image ends up larger than you'd like, you can exclude it. See Excluding images from optimization<\/a>.<\/p>\n<\/blockquote>\n\n\n\n Image Optimization runs on our CDN network, not on your WordPress server, so it never adds load to your hosting. If your site is still slow long after the warm-up window, the cause is almost certainly elsewhere. To confirm, use the fast on\/off test:<\/p>\n\n\n\nWhat helps<\/h2>\n\n\n\n
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After warm-up, pages should be faster<\/h2>\n\n\n\n
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If it's still slow well after warm-up<\/h2>\n\n\n\n