How WebP and AVIF work
Both formats are newer ways of encoding a picture. They use techniques borrowed from video compression to describe the same image with less data, so a photo saved as WebP or AVIF is normally lighter than the same photo saved as JPEG at a similar visual quality, and the visitor sees no difference.
WebP is the older and safer of the two. It handles photographs and flat graphics, supports transparency and animation, and every current mainstream browser displays it. AVIF is newer and generally squeezes harder, particularly on photographs and on images with wide colour or gradients. It also supports transparency. Its trade-off is encoding: producing an AVIF file takes noticeably more processing than producing a WebP, which matters when a site converts images on upload or on the fly.
Why WebP and AVIF matter
Images dominate the weight of most pages, so the format is one of the few decisions that lightens every image at once without changing how the page looks or how it was designed. Nothing has to be redrawn and no layout has to move.
That is worth most on mobile connections, which is how the majority of visitors to a Nepali business site arrive. A lighter hero image means the main content appears sooner and costs the visitor less of their data bundle. It is one of the rare changes that helps speed, cost and experience together, and it can usually be automated once rather than managed image by image.
Common mistakes with WebP and AVIF
The first is converting without resizing. A camera-width photograph converted to AVIF is still a camera-width photograph; the format saves a slice of a file that should never have been that large. Get the dimensions right first, as part of proper image optimisation, then change format.
The second is assuming the format works everywhere. Browsers are fine, but email clients, older in-app browsers, some social preview scrapers and plenty of desktop software are not, so a file that displays perfectly on your site can break in a newsletter or a shared link.
The third is repeated re-encoding. Converting an already compressed JPEG to WebP, then editing and saving again, stacks compression damage that cannot be undone. Keep the original.
How to act on it
Let something else do the work. A capable CMS, image plugin or content delivery network can convert on upload or on request and serve the modern format to browsers that accept it while falling back to JPEG or PNG for anything that does not. That fallback is the whole safety net, so confirm it exists before switching anything.
Then judge the results by eye rather than by file size alone. Compare the original and the converted version at full size, especially on product photographs and images with large flat areas, where aggressive settings show first. Keep the untouched originals in your own storage, and use JPEG or PNG deliberately where a file has to travel outside your website, such as in an email or an attachment.