https://next3offload.com/blog/best-image-file-formats-wordpress/
For most modern websites, the best image file format in 2026 is AVIF, served with a WebP fallback. AVIF typically produces files that are 20% to 50% smaller than WebP at comparable visual quality, while WebP provides excellent browser coverage. PNG still has an important role for transparent graphics, logos, and interface elements. JPEG remains useful for legacy workflows and some photography, but it is no longer the default choice for building a fast website.
Choosing the right image format affects much more than image quality. It influences page speed, Core Web Vitals, bandwidth usage, SEO, and the overall user experience. In many cases, switching formats delivers bigger performance gains than adjusting compression settings alone.
The right decision also depends on your content management system, your audience’s browsers, and how your images are delivered. If your workflow supports automatic optimization, tools like Next3 Offload can generate and serve modern formats without requiring you to choose a file type for every upload.