Convert images to WebP or AVIF for faster pages (and check which one is actually smaller)

PageSpeed Insights flags your images ("Improve image delivery" now, "Serve images in next-gen formats" in older reports), and the standard advice is to convert everything to WebP, or to AVIF if you want the smallest files. I wanted to see whether that holds up, so I converted one batch to WebP, AVIF and JPG at the same time and compared the sizes. AVIF won once out of four. For three big camera photos, the plain JPG beat both newer formats. So this post is less "use format X" and more "measure your own images before you touch your markup", which takes about a minute with the right tool.