Lossless vs Lossy
Lossless keeps every pixel, lossy keeps the file small. Here is what each means for your photos, graphics and web images, and when to choose which.
A clear rule of thumb: lossless for originals and graphics, lossy for sharing and the web, with the real tradeoff spelled out.
How it works
The short answer
Lossless formats keep every pixel exactly as it was. Lossy formats throw away detail you will not notice to make the file much smaller. Use lossless for originals, logos, screenshots and archival copies. Use lossy for photos you want to share or put on the web.
What lossless really means
A lossless format such as PNG, TIFF or lossless WebP and AVIF stores the image so it can be reconstructed perfectly. Save and reopen it a hundred times and the pixels are identical every time. The cost is a larger file, because no information is discarded.
What lossy really means
A lossy format such as JPG, or the default WebP and AVIF, drops fine detail that the human eye struggles to notice. This makes files dramatically smaller. The tradeoff is that every re-encode discards a little more, so repeated saving gradually degrades quality.
When to choose lossy
Choose lossy for photographs you will share, email, or publish on the web. JPG is the classic choice, and WebP or AVIF compress photos even smaller at similar quality. The savings are worth it because viewers cannot usually tell the difference.
When to choose lossless
Choose lossless for anything you may edit again, for logos and graphics with flat colors or transparency, and for long term archives. PNG is the dependable default. Lossless WebP gives the same quality in a smaller file when your audience supports it.
The middle ground
If you must shrink a photo for an upload limit, use a lossy format but stop at the quality that still looks good. The compressors on this site start you at a balanced setting, so you only go lower when a strict size limit forces it.
Format comparison
| Format | Compression | Transparency | Browser support | Best for |
|---|---|---|---|---|
| JPG.jpg | Lossy (discards some detail) | No | All browsers and devices | Photographs and images with smooth color gradients |
| PNG.png | Lossless (keeps every pixel) | Yes | All browsers and devices | Screenshots, logos, illustrations with sharp edges and transparency |
| WebP.webp | Lossy (discards some detail) | Yes | All modern browsers (2011+) | Web images that need both quality and small file size |
| AVIF.avif | Lossy (discards some detail) | Yes | All modern browsers (2020+) | Modern web photos with the best compression at high quality |
Frequently asked questions
Which is better, lossless or lossy?
Neither is always better. Lossless preserves quality, lossy preserves file size. Pick based on whether the image will be edited or archived, or just shared.
Is PNG lossless?
Yes. PNG stores every pixel exactly, which is why it is a good choice for logos, screenshots and archival copies.
Is WebP lossless or lossy?
WebP supports both. Use lossless WebP when you need perfect quality with transparency, or lossy WebP for smaller photos.
Does converting to JPG reduce quality?
JPG is lossy, so conversion discards detail. Keep your lossless original in case you want to edit it again.