How to Compress PNG Files Without Losing Quality

PNG uses lossless compression — but that does not mean PNG files cannot be made smaller. There are several techniques for reducing PNG file size without discarding any image data. Here is how.

Why PNG Files Are Large

PNG stores every pixel losslessly. A 1920×1080 screenshot with millions of distinct colours requires more data than the same dimensions with just a few colours. The more complex the image, the larger the PNG file. Unlike JPG, PNG cannot be 'quality adjusted' downward — but it can be optimised in other ways.

Lossless PNG Optimisation Techniques

• Reduce colour depth: An image with 256 or fewer colours can be saved as an 8-bit 'indexed colour' PNG instead of a 24-bit PNG — often 60–70% smaller with no visual difference
• Remove metadata: PNG files embed author info, creation date, and colour profiles — stripping this EXIF data saves 20–100KB in some files
• Crush the entropy: PNG optimisers reorder the internal data structure for better compression without changing any pixels
• Our Image Compressor applies these optimisations automatically.

When Lossless PNG Compression Is Not Enough

• For photographs saved as PNG (a common mistake), the file will still be 5–10× larger than the equivalent JPG even after optimisation. If your PNG is a photo:
• Convert PNG to JPG — saves 70–90% of the file size
• Convert PNG to WebP — saves 60–80% while keeping transparency support

The Transparency Exception

• If your PNG has a transparent background (logos, product shots, UI elements), you cannot convert to JPG without losing the transparency. In this case:
• Convert PNG to WebP — WebP supports transparency and is 26% smaller than PNG
• Or keep PNG but apply lossless optimisation through the Image Compressor

Target File Sizes for Compressed PNG

• After lossless optimisation, typical PNG file sizes:
• Simple logo (500×300px): 10–30KB
• Screenshot (1920×1080px): 200–600KB (varies enormously by content)
• Photo as PNG (1200×800px): Still 800KB–3MB — convert to JPG or WebP instead
• For a specific file size target, use Compress to 100KB which works across all formats.