Free Image Converter - WebP, AVIF, JPG & PNG
Change format, cap the width, and shrink file size across a whole batch at once - processed on your device and never uploaded.
Runs entirely on your device. Your images are processed in your browser and never uploaded. There is no server to send them to, so we never receive, store, or see your images - and filenames are hidden from our analytics too. Load this page, disconnect from the internet, and it still works.
Convert and resize images
Output format
Quality
82%
Images wider than this are scaled down. Aspect ratio is kept.
Which format should you actually use
WebP is the safe default for the web in 2026: every current browser supports it, and at matched quality it is typically 25-35% smaller than JPEG and dramatically smaller than PNG for photographs. AVIF compresses harder still, often 20-30% below WebP, but encoding is slower and browser support for encoding (as opposed to display) is less consistent - this tool checks whether your browser can actually produce AVIF before it tries, rather than silently handing you a PNG in disguise. JPG remains the right answer when a file has to open in older desktop software or be emailed to someone on a legacy system. PNG is for graphics, screenshots, logos, and anything needing transparency - never for photographs, where it produces files many times larger than necessary.
Why max width usually matters more than format
A photo straight off a modern phone is often 4000 pixels wide. No layout on any website displays it at that size; the browser downloads every one of those pixels and then throws most of them away. Capping the width is frequently a bigger saving than changing format at all. As a working rule: hero images at 1920-2400 pixels, in-content images 800-1200, thumbnails around 400. Set the max width field and the whole batch is scaled proportionally on the way through - aspect ratios are preserved, and images already narrower than the cap are left alone.
Batch conversion without an upload queue
Everything here runs through the browser canvas API on your own machine, so there is no upload, no queue, no daily limit, and no watermark. Practically, that means you can push forty images through in one go without an account, and confidential material - client work, unreleased products, internal screenshots - never leaves your device. The trade-off is that your own hardware does the work, so a large batch of very high-resolution images will take longer on an older laptop than on a new one.
Frequently Asked Questions
No. Conversion and resizing run in your browser using the canvas API. No image data leaves your device, is stored, or is logged, and filenames are masked from our analytics. Disconnect from the internet after the page loads and it still works.
WebP unless you have a specific reason not to: universal support and excellent compression. AVIF compresses further and is worth it for large photographic hero images, but encoding is slower and not every browser can produce it. This tool tells you if yours cannot rather than quietly giving you something else.
Around 80-85% is the sweet spot for web photos - large savings with no visible difference at normal viewing sizes. Go lower, to 60-70%, for backgrounds and thumbnails. Go higher, toward 90-95%, only for photography portfolios where fine detail is the product.
No. Setting a max width scales the whole image down proportionally and preserves the aspect ratio. Nothing is cropped, and images already narrower than your cap are passed through untouched.
Up to 40 per batch. The limit protects your browser's memory rather than any server capacity, since your machine does all the work. Run several batches if you have more.
Yes. Re-encoding through the canvas discards embedded metadata, including GPS coordinates and camera information. That is usually desirable when publishing photos to the web, but keep your originals if you rely on that data.
Right Format, Wrong Everything Else?
Format is one of about a dozen things that decide whether a page feels fast. We audit the rest - hosting, render-blocking scripts, layout shift - and fix what actually costs you visitors.