Image Compressor
Reduces file size while preserving quality.
This tool runs on JavaScript. To use it, turn on JavaScript in your browser and reload the page.
THE SAME PICTURE, A MUCH SMALLER FILE.
Image Compressor reduces the file size of photos and images while keeping their quality. You do not have to pick a quality level: on each attempt the tool compares the output with the original (the SSIM similarity measure) and chooses the lowest quality that is still visually identical. Flat-coloured graphics and screenshots look exactly the same at much lower quality, so they shrink noticeably; on detailed, textured photos the quality is raised so no blocking artefacts appear. The output format can be WebP (best compression), JPG (opens everywhere), AVIF (smallest file, newer browsers) or PNG (lossless, limited compression). You can upload JPG, PNG, WebP, AVIF, HEIC and more.
“Quality bias” (−15 to +15) shifts that choice: a negative value means a smaller file, a positive value means higher quality. You can also give a target size in KB; the quality is then set by binary search to the highest value that stays under the target, and if the target cannot be met this is stated plainly. For the web the biggest win usually comes from reducing the dimensions: “Maximum width” can cap the image at 2560, 1920, 1280 or 800 pixels, and small images are never enlarged. The output is never larger than the source — the quality is lowered step by step, and if it still comes out bigger you are told the source was already efficient. EXIF data (location, device, date) is removed from the output by default; it can be kept if you need it. Compression is lossy except for PNG: the discarded information does not come back, so keep your archive copy and produce the web version here. You can upload up to 20 images at once; they are all processed with the same settings, and several files download as a single ZIP.
From start to finish
- Upload your image. Drag the file in or select it. Its dimensions and size are read.
- Choose the format and, if you want, a target. WebP is the right starting point for most sites, and you do not need to touch the quality. If you have to meet a limit, enter the target size in KB; for a form with a 100 KB limit, for example, 95 KB. If the image will be shown 1200 px wide on screen, set the maximum width to 1920 or 1280.
- Compress and download. The chosen quality, the measured similarity, the new size and the saving are shown on screen. Download it; the copy on the server is deleted when you leave the tool.
Frequently asked questions
WebP or JPG?
At the same visual quality WebP is noticeably smaller than JPG and it carries transparency; every current browser opens it. If you are going to attach it to an email, use it in an old program or send it to print, JPG. AVIF is smaller still, but some programs do not open it yet.
Can I not choose the quality myself?
You do not enter a percentage directly; the tool chooses it by looking at the similarity measure. You set the direction with “Quality bias”: moving it down means a smaller file, moving it up means higher quality. If you need to get under a specific size, use the target KB field.
The file did not get smaller. Why?
If the source was already compressed efficiently, re-encoding it can make it bigger. In that case the tool does not hand back a larger file and says so. Reducing the dimensions usually gives a bigger saving.
Does my file stay on the server?
No. Your file reaches the server only to be processed and is deleted when the job is done; the output is deleted too once you download it and leave the tool. You don't need an account, a name or an email address, and your files are never sent to a third-party service. It is free to use: we set no hourly or daily quota on the number of jobs, we don't make you watch an ad before processing, and we add no watermark to the output.
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