How to compress images without making them blurry: PNG, JPG, WebP, and AVIF

Images are often the largest resources in web pages, documents, and chat attachments. The available savings depend on source content, pixel dimensions, original format, prior compression, and acceptable visual quality; no fixed reduction applies to every image. This guide connects format choice and settings with a reproducible visual review.

Lossy vs lossless compression

Lossless compression, such as PNG, reduces size without discarding pixel data. It suits screenshots, line art, and images that need transparency, but it cannot shrink photos very much. Lossy compression, used by JPG and the lossy modes of WebP and AVIF, removes details that people are unlikely to notice in exchange for much smaller files. It is ideal for photos and illustrations, and is usually the best choice for everyday photography.

Choosing between four formats

• JPG: Suits continuous-tone photos and is generally easier to open across editors, office software, and chat tools outside the browser.
• PNG: Suits screenshots, icons, and line art that need lossless pixels, transparency, or sharp edges. Photos are often large, though not universally.
• WebP: Supports lossy, lossless, and transparent images and works well for modern web delivery, but it must be tested against the source to confirm a smaller result.
• AVIF: Is often competitive for photos, gradients, and low-bitrate output; encoding cost and compatibility with non-browser software also belong in the decision.

Setting the quality level

SnapshotLab provides a 1–100 slider for lossy output, but it is an encoder setting, not a percentage quality score that can be compared directly across JPG, WebP, and AVIF. PNG is lossless output and does not use this quality value.

• Starting point: Make one output at the default 80. It is a trial starting point, not the best value for every image.
• Find the lower threshold: Reduce in steps of 5–10, inspect at the actual display size and 100%, and return to the previous step when text edges, skin, or gradients show unacceptable artifacts.
• Recalibrate by format: Do not assume two outputs at 80 have equal quality. Adjust each to a similar appearance before comparing byte size.

Record both output bytes and the visual review. Savings alone encourages over-compression, while the slider number alone cannot compare different encoders.

Compress for free in your browser—without uploads

1. Open the image compressor.
2. Drop in or select one or more images.
3. Adjust the compression quality slider and choose an output format—WebP or AVIF are good options.
4. Select Start processing, compare the before and after sizes, and download the results individually or together as an archive.

🔒 Everything happens locally in your browser. Your images are never uploaded to a server.

Common mistakes

• Compressing repeatedly: Every lossy pass reduces quality, so avoid recompressing the same image.
• Assuming photo PNGs are always a fixed multiple larger: They are often large, but the ratio depends on content and output settings and must be measured.
• Always choosing 100: A higher setting may greatly increase bytes, but only the target image can show whether it produces a useful visual gain.