Converting multiple images at once
Select any number of PNG, JPG, GIF or BMP images and convert them all to WebP or AVIF in one pass - both modern formats that typically produce much smaller files than PNG or JPG at a similar visual quality, which speeds up page loads. Everything happens in your browser; files are never uploaded anywhere, and each converted image gets its own download link.
AVIF encoding support varies by browser - if your browser cannot encode AVIF, the conversion falls back to another format automatically and this tool tells you so, rather than silently producing the wrong file type.
Why this tool exists specifically for batches rather than one image at a time
Converting an entire site's or project's worth of images to a modern format one file at a time is tedious and easy to do inconsistently - selecting a whole batch and converting them together in one pass, with the same format and quality setting applied uniformly, is what makes a full site-wide format migration practical rather than a slow, repetitive chore.
How this differs from this site's single-image converter and optimizer tools
The site's general image converter and optimizer tools are built for working on one image at a time with more granular control - this tool is built specifically for the batch case: many images, the same target format and quality applied to all of them at once, which is the more practical workflow when migrating a whole folder of images rather than fine-tuning one.
Why AVIF encoding sometimes silently wasn't actually possible until this tool told you
AVIF is a newer format than WebP, and not every browser's built-in encoder supports producing it yet, even though most browsers can display an AVIF file just fine - the gap between "can display" and "can encode" is why a browser that can't encode AVIF falls back to a different format automatically, and why this tool explicitly tells you when that happened rather than quietly mislabeling a file's actual format.