PNG files don't respond to quality sliders the way JPEG does. PNG is lossless — every pixel is stored exactly, and there's no "quality" knob to turn down. This confuses a lot of people who drag a PNG into a compressor, move the slider to 50%, and wonder why nothing changes or why the output is a different format than expected.
Here are the four methods that actually reduce PNG file size, ordered by how much reduction they typically achieve.
WebP is the most effective single-step way to reduce a PNG's file size for web use. At 85% quality, WebP achieves the same visual quality as the source PNG at roughly 50–80% of the file size. The difference is meaningful: a 2MB PNG screenshot might become a 400KB WebP that looks identical on screen.
WebP supports transparency — so if your PNG has a transparent background, that transparency is preserved in the WebP output. All modern browsers support WebP. For web images, this is the default recommendation.
Our PNG compressor converts to WebP directly in your browser — no upload, no account. If you want more control over the conversion, the dedicated PNG to WebP converter includes a quality slider and transparency preview.
For photographs saved as PNG — product photos, hero images, portraits — converting to JPG at 85–90% quality typically produces a file 60–85% smaller than the PNG, with no visible quality difference for photographic content.
The tradeoff: JPG cannot store transparency. If your PNG has a transparent background, those areas become solid white (or another fill colour you choose) in the JPG. For logos, icons, and graphics where transparency matters, JPG is not the right choice. For photographs on white or coloured backgrounds, it almost always is.
One caution: if you convert a PNG graphic to JPG, you may see JPEG artifacts — subtle blurring and colour banding — around sharp edges and text. JPEG compression handles gradients well but struggles with the hard boundaries that are common in logos and UI screenshots.
This is the method people underestimate. Halving the width and height of an image reduces its pixel count by 75% — and file size scales with pixel count. A 2400×1800 PNG contains four times as many pixels as a 1200×900 PNG of the same content. The file size difference is substantial even though the dimensions only dropped by half.
For web use, serving an image at larger dimensions than it displays is one of the most common sources of unnecessary file size. A product photo displayed at 600px wide does not benefit from being stored at 2400px wide. Reducing to the display size — or to 2× for retina displays — keeps the file size proportionate to the actual need.
The key advantage of dimension reduction is that it works regardless of format — you get a smaller PNG output without changing the format at all. The tradeoff is that you lose pixel data permanently; the image can't be scaled back up without quality loss.
Standard PNG files often contain redundant data: EXIF metadata, colour profiles, text chunks, and suboptimal compression parameters. Lossless PNG optimisers — tools like ImageOptim (Mac), pngcrush, and oxipng — re-encode the file using better compression settings and strip non-essential metadata. No pixel data is changed; the file is simply stored more efficiently.
The typical saving is 10–30%. That's meaningful for large libraries of PNG files, but it won't turn a 5MB PNG into a 500KB file. For significant size reduction, one of the first three methods is necessary.
Browser-based tools including our PNG compressor strip accessible metadata during conversion, but the most thorough lossless optimisation is done by dedicated desktop tools that can apply multiple compression passes.
| Your situation | Best method |
|---|---|
| Web image, any content type | Convert to WebP |
| Photograph without transparency | Convert to JPG |
| Image is too large for its display size | Reduce dimensions |
| Must keep PNG format, minor size reduction OK | Lossless PNG optimisation |
| Logo or graphic with transparency | Convert to WebP (preserves transparency) |
The content type of your PNG matters more than the compression method you choose. A PNG of a photograph — complex gradients, millions of unique pixel values — will always be large regardless of the PNG compression level, because lossless compression has almost nothing to find and exploit. A PNG of a logo with flat colours and sharp edges compresses extremely well because large areas of identical pixel values can be encoded very efficiently.
This is why PNG is genuinely the right format for graphics and screenshots, not just a misguided habit. It's also why "compressing" a photographic PNG without converting formats produces negligible results — the format is the constraint, not the compression settings.
PNG uses lossless compression — every pixel is stored exactly. Unlike JPEG, there is no quality slider that trades visual quality for file size while keeping the PNG format. Tools that claim to compress PNG without changing formats are stripping metadata — useful but minor. For significant size reduction, convert to WebP or JPG.
At 85%+ quality, WebP looks identical to the source PNG on screen for photographic content. The file is encoded more efficiently, not degraded visibly. For flat-colour graphics, WebP lossless mode exists as an option that preserves quality exactly.
Yes, but the savings are modest — typically 10–30%. Lossless PNG tools re-encode with better compression and strip metadata. To achieve 50–80% reduction, format conversion to WebP or JPG is necessary.
PNG-8 uses a 256-colour palette and produces much smaller files. PNG-24 stores full colour depth and is larger. For simple graphics with few colours, PNG-8 can be significantly smaller with no visible difference. For photographs or gradients, PNG-8's 256-colour limit causes visible banding.
WebP is typically 25–35% smaller than JPG at the same visual quality, so WebP usually produces the smaller output. JPG has broader compatibility — it opens in every editor, email client, and platform. Use WebP for web performance; use JPG when you need the file to open everywhere without software limitations.