Image Format Comparison
See which image format gives the smallest file for your picture. The tool compresses the same image as JPG, WebP, AVIF and JPEG XL at one quality setting, then shows the file sizes, an objective quality score and a zoomed side-by-side view so you can judge the artifacts yourself. Everything runs in your browser.
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Drag either image to move both views together. Zoom in on edges, text and smooth gradients to see compression artifacts.
How to use the Image Format Comparison
- Choose an image, or keep the built-in test picture. Photos, screenshots and graphics behave very differently, so test the kind of image you actually publish.
- Set the quality and pick the formats to compare. Use the test size option to keep AVIF and JPEG XL encoding fast.
- Press Compress and compare. JPG and WebP finish instantly; AVIF and JPEG XL may load a WebAssembly encoder first.
- Read the table: smaller file size and higher PSNR are better.
- Inspect the details in the side-by-side viewer at 2× to 8× zoom, then download the files you want to keep.
JPG, WebP, AVIF and JPEG XL at a glance
| JPG | WebP | AVIF | JPEG XL | |
|---|---|---|---|---|
| Introduced | 1992 | 2010 | 2019 | 2021 (ISO standard 2022) |
| Based on | 8×8 DCT blocks | VP8 video intra-frames | AV1 video intra-frames | Variable-size DCT plus modular mode |
| Transparency | No | Yes | Yes | Yes |
| Animation | No | Yes | Yes | Yes |
| Bit depth | 8-bit | 8-bit | 8, 10 and 12-bit, HDR | up to 32-bit float, HDR |
| Lossless mode | No (in common use) | Yes | Yes | Yes, plus lossless JPEG recompression |
| Browser display | All | All current | All current | Safari; others behind flags or not at all |
| Typical artifacts | Blocks and ringing around edges | Blur and smeared fine texture | Smoothing of fine texture and grain | Mild blur, good texture retention |
How to read the results
- Bits per pixel is the file size in bits divided by the number of pixels. Uncompressed RGB uses 24; a good web photo typically uses 0.5 to 2.
- PSNR is calculated as 10 × log10(255² ÷ MSE), where MSE is the mean squared difference of the red, green and blue values between the decoded and original image.
- Look where codecs struggle: small colored text (chroma subsampling), dark smooth gradients (banding), fine grass or hair (texture smoothing) and sharp edges on flat colors (ringing). The built-in test image contains all four.
Tips for choosing a web format
- Serve AVIF or WebP with a JPG fallback in a
<picture>element to get small files without leaving older software behind. - Tune quality by eye at 100% zoom on a real screen, not by the number alone. Quality 50 in AVIF often looks like 75 to 80 in JPG.
- Ready to convert a whole folder? Use Image to AVIF, the WebP Converter or the Image Converter.
Frequently asked questions
Which image format is the smallest?
For photos, AVIF and JPEG XL usually produce the smallest files at similar visual quality, often 30 to 50 percent smaller than JPG, with WebP in between at roughly 25 to 35 percent smaller. The exact numbers depend heavily on the picture, which is why this tool tests your own image instead of quoting averages.
Does the same quality number mean the same quality in every format?
No. Each encoder has its own quality scale, so quality 75 in JPG, WebP, AVIF and JPEG XL produces different amounts of detail. That is why the table also shows PSNR, a measurement of how close the decoded pixels are to the original. To compare fairly, look for the format with the smallest file at a similar PSNR, or adjust the slider until the images look the same to you.
What is PSNR?
Peak signal-to-noise ratio compares every decoded pixel with the original and expresses the average error in decibels. Higher means more faithful: around 30 dB shows visible artifacts, 35 to 40 dB is good, and above roughly 40 dB differences are very hard to spot. PSNR does not perfectly match human perception, so always check the zoomed view too.
Can every browser display AVIF and JPEG XL?
AVIF is supported by all current major browsers. JPEG XL is displayed natively by Safari, but Chrome and Firefox do not show it by default, so it is mainly useful for archiving and apps today. WebP and JPG work everywhere. Websites commonly serve AVIF or WebP with a JPG fallback using the HTML picture element.
Why does AVIF or JPEG XL take longer?
These newer codecs search much harder for an efficient way to describe the image. When the browser has no built-in encoder, the tool downloads a WebAssembly build of the reference encoder (about 2 to 3 MB) and runs it on your device. Choosing a smaller test size makes it much faster.
Is my image uploaded to compare formats?
No. All encoding, decoding and measuring happens in your browser. The image is never sent to a server; only the encoder code itself is downloaded when AVIF or JPEG XL is needed.
Why is a format larger than JPG for my image?
Very small images, pixel art, screenshots with few colors or images saved at a very high quality can favor one encoder over another, and transparency is removed for this comparison. For flat graphics a lossless PNG or WebP may even be best. The comparison shows what works for your specific picture.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.