How to compress a PNG image

Drop your PNG files into the box above, or click to select. Add as many as you like. No cap on count or size.
Wait a moment while the tool re-encodes each file inside your browser. Larger files take a little longer, which is just the reality of re-encoding anything substantial on your own CPU.
Download the results. Each file gets its own link, or you can use Download all to grab everything at once.

Your files never leave your computer, no account is required, and there’s no watermark or upgrade prompt waiting at the end. That’s it.

Why PNG files get so large

PNG (Portable Network Graphics) is a lossless raster format defined in 1996. Every pixel of the original image is preserved exactly, which is perfect for screenshots, logos, line art, and anything with transparency. The trade-off: lossless preservation produces big files. A single high-resolution screenshot can easily top 5 MB.

Three main reasons PNGs get so fat:

High color depth. A standard PNG stores 24 bits of color per pixel plus an optional 8-bit alpha channel. That’s four bytes per pixel before compression even begins.
Inefficient palette use. Many PNGs encode photographic data when an indexed palette of 256 colors would be plenty and produce a file several times smaller.
Suboptimal encoder settings. Most software writes PNGs with defaults that prioritize compatibility over file size, leaving 20–80% of bytes on the table.

Our compressor re-encodes your PNG using the browser’s native encoder, strips unnecessary metadata, and rewrites the file more compactly. Transparency, color accuracy, and dimensions are all preserved.

Lossless vs lossy PNG compression

Two very different approaches to making PNG files smaller, often conflated in marketing:

Lossless compression rewrites the file with more efficient encoding but keeps every pixel byte-for-byte identical. Tools like pngcrush, optipng, and zopflipng do this. Savings typically run 5–30%.
Lossy compression reduces the number of distinct colors and quantizes pixel values, often shrinking files by 50–80% with little visible difference. Tools like pngquant and TinyPNG use this technique.

Our compressor runs in your browser and uses the platform’s native PNG encoder. For most screenshots and UI graphics, expect 30–70% savings. If your image has already been heavily optimized elsewhere, the further savings will be modest, which is the honest outcome for any compressor working on pre-compressed input.

When to use PNG (and when not to)

PNG is the right format when you need:

Crisp edges in icons, logos, illustrations, and UI mockups.
Transparency for stickers, overlays, and decorative graphics.
Lossless fidelity for screenshots that may be inspected pixel-by-pixel.

PNG is the wrong format when you have:

Photographs. JPEG or WebP will be 5–10× smaller at the same perceived quality.
Animations. Use animated WebP or APNG, or better, a video element.
Vector content. SVG scales to any size at a fraction of the bytes.

If you’re publishing a photograph that happens to be in PNG, convert it to WebP instead. The savings will dwarf anything a PNG-only compressor can offer.

How our PNG compressor protects your privacy

Most “free” online image compressors upload your files to a remote server. Three problems come with that:

Privacy risk. Your image (which might contain a screenshot of an internal document, unreleased design, or personal content) gets sent across the internet to a third-party server, where it may be cached, logged, or retained.
Bandwidth cost. Uploading a 50 MB file over a slow connection takes minutes. Compressing locally takes seconds.
Service limits. Server-side compressors have to impose file-size and rate caps to keep their costs bounded. We don’t.

Our tool uses the browser’s built-in <canvas> and toBlob() APIs to do everything locally. Open DevTools, switch to the Network tab, and watch: zero outbound requests for your file data. The page itself loads HTML, CSS, and a small JavaScript file. Nothing else.

Tips to get the best PNG compression results

Start with the highest-quality source you have. Compressing an already-compressed file rarely beats compressing the original.
Crop before compressing. Removing unused borders or empty space is the single biggest win on screenshots, every time.
Resize to display size. A PNG shown at 800 px wide doesn’t need to be 4000 px wide. Resize first, compress second.
Strip transparency if you don’t need it. A PNG with an opaque background can often be re-saved as JPEG with 90%+ savings. Try our JPG compressor on the result.
Run files through twice if needed. Re-running a compressed PNG occasionally squeezes out a bit more.

Common PNG compression mistakes

Using PNG for photographs. Still the most common waste of bandwidth we see on the modern web. Photos compress 80–90% smaller as JPEG or WebP with no visible difference.
Trusting “lossless” labels blindly. Many tools advertised as lossless are actually lossy under the hood. We’ll be explicit: this tool re-encodes through the browser’s native PNG encoder and drops redundant chunks, but preserves visible image data.
Compressing the same file repeatedly. PNG re-encoding is largely deterministic. After one or two passes, you’ve pulled out nearly all the savings that are available.

Compress PNG