How to use it
- 1.Drop your images on the page, paste one from the clipboard, or click “Choose images”. JPG, PNG, WebP, AVIF and iPhone HEIC photos all work.
- 2.Each image is compressed right away with quality 75, keeping its format. The list shows the old and new size of every file.
- 3.To save more, lower the quality, choose “Limit dimensions” for large photos, or save as WebP or AVIF. Every image is compressed again when you change a setting.
- 4.With a single image, drag across the before and after view (or open it at 100 %) to check the quality. Then download the files one by one or all together as a ZIP.
Lossy and lossless compression
JPG, WebP and AVIF are lossy: they throw away detail the eye barely notices, such as fine colour variation and noise. The quality setting decides how much. Between 70 and 80 a photo usually looks the same as the original at a fraction of the size; below 60, blocky patches and halos around edges start to show.
PNG is lossless: every pixel is kept exactly. The tool first repacks the file with OxiPNG, which on its own saves 5–30 %. Reducing the image to 256 carefully chosen colours (the trick TinyPNG uses) typically saves 60–80 % more. That works well for screenshots, logos and illustrations; for photos, JPG or WebP will be far smaller than any PNG.
Why phone photos are so big, and the quickest fix
A modern phone saves 12 to 48 megapixel photos of 3–10 MB each. A laptop screen shows about 2 megapixels, and messaging apps and websites scale pictures down anyway. Choosing “Longest side 1920 px” cuts the number of pixels by around 80 %, and the file size with it, before quality even comes into play.
Changing the format helps too. At the same visual quality WebP is about 25–35 % smaller than JPG, and AVIF often half the size. Both open in every current browser; for photos you send to people or upload to older systems, JPG is still the safest choice.
What happens to metadata
Compressed images keep only their pixels. Camera details, dates, the colour profile and EXIF data, including the GPS location many phones record, are not copied to the new file. That saves a few kilobytes and is good for privacy when you share photos.
If an image is already compressed so well that re-encoding it would not make it smaller, the tool keeps the original file unchanged (with its metadata) and marks it “already optimised”.
Questions and answers
Are my images uploaded?
No. Compression runs in your browser, on your device, with the open-source codecs Google’s Squoosh uses: MozJPEG, libwebp, libavif and OxiPNG. No image is sent to nestoo or anyone else, and the tool keeps working offline once the page has loaded.
How much smaller will my images get?
Photos straight from a camera or phone usually shrink by 50–80 % at quality 75, and by 90 % or more when you also limit the dimensions. Screenshots and graphics saved as PNG typically lose 60–80 % with the 256 colour reduction. Images that were already compressed for the web may only shrink a little.
Will compression reduce the quality?
Lossy compression always removes some detail, but at quality 70–85 it is very hard to see. Use the before and after view at 100 % to check fine textures, text and smooth skies, which show artefacts first. Turning off “Reduce PNGs to 256 colours” keeps PNGs pixel for pixel identical.
How do I compress a photo to under 100 KB or 200 KB?
The tool doesn’t aim for an exact size, but it shows the new size instantly, so you can adjust until it fits. For a typical phone photo, limiting the longest side to 1280 px at quality 75 gives around 150–300 KB; 1024 px or a quality of 60 brings most photos under 100 KB. Saving as WebP makes it smaller still.
Can I compress many images at once?
Yes. Add as many images as you like; they are compressed one after another with the same settings, and “Download all as ZIP” saves them in a single file. File names stay the same, so you can put the compressed copies straight back where the originals were.