How we picked these tools
We judged each compressor on three things: how much it actually shrinks a PNG, how much quality you give up to get there, and whether your file leaves your device. A few links to paid services below are affiliate links, so we may earn a commission if you subscribe — at no extra cost to you. Our affiliate disclosure covers how that works. It has no bearing on which tools made the cut or where they land in the list.
1. PNGifier — best free, private compressor for everyday files
PNGifier compresses PNGs entirely inside your browser, so the file you drop in never travels to a server. There is no account, no daily quota counting down, and no watermark — just drag a PNG into the compress-png tool and download a lighter version. It is the option we reach for first because it covers the common case — icons, screenshots, and web graphics — without any of the friction the cloud tools add.
Because the work happens on your own hardware, very large batches of high-resolution photos will lean on your machine rather than a render farm, and there is no API to wire into a build pipeline. For private files and quick wins, though, that local-first approach is exactly the point.
2. TinyPNG — best smart lossy compression
TinyPNG popularized the smart-lossy approach: it analyzes the image and selectively reduces the color palette, which routinely cuts a PNG by 60 to 70 percent while staying hard to tell apart from the original. For flat illustrations and UI assets the results are excellent, and the drag-and-drop page could not be simpler.
Your images are uploaded for processing, the free web tool caps you at a handful of files per batch, and serious volume or its WordPress and developer API need a paid plan. As a pure size-versus-quality engine, though, it is still one of the best around.
3. ShortPixel — best for bulk and WordPress sites
ShortPixel is built for people who compress thousands of images, not three. It offers lossless, lossy, and a middle "glossy" mode, a generous credit-based pricing model, and a WordPress plugin that optimizes your whole media library and can serve modern formats automatically. That makes it a favorite for site owners chasing faster load times at scale.
It is more of a service than a one-click toy, so there is a little setup, and the heavy lifting happens on ShortPixel's servers rather than your browser. If you run a content-heavy site, the bulk-processing power easily justifies it.
4. Squoosh — best for hands-on, side-by-side tuning
Squoosh is a free, open-source web app from the Google Chrome team that runs its compression in the browser. Its standout feature is the split preview: drag a slider to compare the original against the compressed version in real time, adjust the palette and quality, and watch the file-size readout change as you go. It is the best way to learn what a setting actually costs you.
It works one image at a time, which makes it more of a tuning bench than a batch processor, and the wealth of options can feel like a lot for a quick job. For deliberate, quality-critical compression, it is superb — and entirely private.
5. ImageOptim — best free desktop compressor for Mac
ImageOptim is a free Mac app that bundles several respected optimizers behind a single drag-and-drop window. Drop in a PNG and it strips metadata and runs lossless crushers in one pass — and if you enable its lossy mode, it leans on a pngquant-style palette reduction for bigger savings. Files are processed locally and overwritten in place.
The obvious limitation is that it is Mac-only, so Windows and Linux users need a different pick. For designers and developers on a Mac who want a free, install-and-forget compressor, it is a desktop staple.
How to choose a PNG compressor
First decide whether the image can tolerate lossy palette reduction — if it can, that is where the dramatic savings live. Next, weigh privacy: a screenshot of a contract or an unreleased design belongs in a tool that never uploads it. Then match the tool to your volume, from a one-click browser page for a single file to a bulk service for a whole media library. If you mostly handle ordinary PNGs and value speed and privacy, the simplest local tool will serve you best.
Why a browser tool wins for most compression jobs
Today's browsers can run the same compression algorithms the cloud services use, right on your device. That means no upload, no waiting in a queue, no quota, and nothing for a third party to store or leak. For the everyday job of trimming a PNG down to a sensible size, it is both faster and more private — which is why we built our PNG compressor to work this way.
Frequently asked questions
- Lossless or lossy — which PNG compression should I use?
- Use lossless when the image has to stay pixel-perfect, such as a logo with sharp edges or a screenshot with text. Use lossy palette reduction when the file is too big and small color shifts are acceptable, because it routinely cuts PNG size by 60 to 70 percent. Many people compress losslessly first and only reach for lossy when they need a smaller file.
- Will compressing a PNG make it blurry?
- No. PNG compression does not blur or soften an image the way over-compressed JPG can. Lossless compression is identical to the original, and lossy PNG tools work by reducing the number of distinct colors, so the worst case is slight banding in smooth gradients — never the smeared look people associate with low-quality JPGs.
- Is it safe to upload private images to a compressor?
- Cloud compressors are convenient but they receive a copy of your file, so anything sensitive is safer in a tool that compresses on your own device. An in-browser compressor like PNGifier never sends the image anywhere, which sidesteps the question of how long a service keeps your uploads.
- How much smaller can a PNG actually get?
- It depends on the image. Flat graphics, icons, and screenshots with limited colors can drop 50 to 70 percent with lossy palette reduction and very little visible change. Photographic PNGs compress far less, and if you are squeezing one of those, converting to WebP or JPG usually beats any PNG compressor.