Compress PNG online. Up to 80% smaller,
same quality.

How to compress PNG files online

Compressing PNG with HyperPNG is a three-step flow. Drop a PNG file (up to 20 MB) onto the upload area at the top of the page, optionally pick a resize percentage if you also want smaller dimensions, and click Compress PNG. The result lands a few seconds later, ready to download. There is no signup, no watermark, and no daily limit for casual use — registered users get a higher quota and 30-day history of every compression.

You can drop multiple PNGs at once — HyperPNG processes a batch of up to 30 files in parallel. The same quality settings apply to every PNG in the batch, so a folder of screenshots or icons can be optimised in a single pass.

Why reduce PNG file size?

PNG is a lossless format, which is why designers love it for screenshots, icons, logos, and any artwork that needs pixel-perfect edges or alpha transparency. The trade-off is size. A single 1080p screenshot can easily weigh 2–3 MB. Ten of them on a documentation page push your page weight past 25 MB before you even add any other assets.

That hurts in three places: web performance (slow Largest Contentful Paint, worse Core Web Vitals, lower search ranking), bandwidth costs (mobile users on metered plans bounce when a page is too heavy), and storage (asset bundles, design libraries, and Git repositories grow far faster than they need to). A good PNG compressor solves all three at once: smaller PNG file size, same visible quality, no extra effort.

PNG vs JPEG: when to compress what

Picking the right format is half of the battle. PNG is the right choice when you have flat colour areas (illustrations, UI mockups, logos), sharp edges (text, vector art exported as raster), or you need transparency. JPEG wins for photographs with lots of subtle colour gradients — its lossy DCT compression is purpose-built for that kind of content. WebP and AVIF can sometimes beat both, but support is still spotty for some workflows.

If your image is genuinely a photograph that ended up as a PNG, the right move is to convert it to JPEG before you compress — you will save much more than any PNG size reducer can squeeze out. If your image really wants to be a PNG, our compressor is what you want.

Lossy vs lossless PNG compression

There are two ways to compress PNG files. Lossless compressors (zopflipng, oxipng, pngcrush) reorganise the underlying data without changing a single pixel. They are perfect for archival purposes but typically only shave 10–25% off the file size. Lossy compressors rebuild the image with a smaller, hand-picked colour palette — visually identical to the original on most images, but typically 60–80% smaller.

HyperPNG uses lossy palette quantisation by default because the quality difference is usually invisible while the size win is dramatic. If you spot any banding on a particular image, open Advanced and raise the minimum quality — the compressor will refuse to write a file below that threshold, giving you a clear knob between size and fidelity.

How HyperPNG compresses PNG images

Under the hood we run an open-source palette quantiser, tuned with a quality range of 65–90 and metadata stripping enabled by default. Quality 90 is the upper bound — output never exceeds that fidelity — and 65 is the floor; if the engine cannot meet the floor, the compression is aborted rather than producing a visibly degraded image. Together, these defaults are tuned to be visually indistinguishable from the original on typical UI imagery, screenshots, illustrations, and game art.

Every PNG we process keeps its full alpha channel, including semi-transparent edges around antialiased text or rounded corners. Metadata chunks (iCC, EXIF, time, comments) are stripped because they add bytes without ever showing up on screen. The actual compression runs in a worker queue, so the browser never blocks while a larger PNG is being optimised.

Tips to make PNG files smaller without losing quality

• Resize first. If your PNG is 4000×3000 px and you only display it at 800×600, resize before compressing. The HyperPNG resize presets (25%, 50%, 75%) do this in one step. Halving the dimensions reduces the pixel count by 4× — usually a bigger win than any palette quantisation.
• Strip metadata. Screenshot tools and photo apps often embed colour profiles, timestamps, and editor signatures. HyperPNG strips them automatically, but if you are using another tool, double-check it does the same.
• Match the palette to the content. Flat illustrations and UI screenshots compress best — they often shrink by 80% or more. Photographs and gradient-heavy renders compress less; switch to JPEG, WebP, or AVIF for those.
• Compress once. Repeated rounds of lossy compression on the same PNG accumulate artefacts. If you need to edit later, keep the original and re-export from source.
• Check the result on the actual background. Transparency is preserved, but look at semi-transparent edges over your real backdrop, not just over a checker pattern in the preview.

How HyperPNG compares to other PNG compressors

There are plenty of free PNG compressors online. The differences come down to four things: quality of the underlying engine, the file-size limit, whether they keep your files private, and whether they push you into a paid tier for basic use.

HyperPNG is built around the same class of palette-quantising engine that powers the most accurate competitors — and we accept files up to 20 MB without paywalling that limit. Every upload is auto-deleted within 24 hours; registered users can keep history for 30 days but can wipe it any time from the dashboard. We do not train on your images, do not run third-party tracking on the upload form, and never add a watermark. If you came here looking for a TinyPNG alternative or a free PNG optimizer that just works, you are in the right place.

When not to use a PNG compressor

If you are archiving original assets, compressing a PNG that is going into a print pipeline, or working with medical or scientific imagery where every pixel matters, stick with lossless tools or do not compress at all. Lossy PNG compression is fantastic for the web, for documentation, for screenshots, and for ship-it-now design assets. It is the wrong choice when fidelity is non-negotiable.