Why Are PNG Files So Large? (And How to Shrink Them)
Not a bug - it's how PNG works. Here's why PNGs get so big, and what genuinely helps.
It's a common surprise: the same photo saved as PNG can be five or ten times larger than saved as JPG. That's not a mistake or a bad export setting - it's a direct result of what PNG is built to do.
The real reason: lossless compression
PNG never discards any image data - every pixel is preserved exactly as it was. That makes it ideal for content with flat colors and hard edges, like logos, icons, and screenshots with text, which compress extremely well under those rules. But a photo is the opposite of that: millions of subtly varying colors, which lossless compression can't simplify away nearly as effectively as JPG's lossy approach can.
What actually shrinks a PNG
- Compress the PNG - lossless optimization and palette reduction can trim meaningful size, especially for graphics and screenshots, without changing how it looks
- If it's a photo and doesn't need transparency, convert it to JPG or WebP instead - this is where the biggest size drop happens
- If it needs transparency but not perfect losslessness, WebP supports transparency too, at a fraction of PNG's size
When PNG is worth the extra size
If the image is a logo, icon, screenshot with text, or anything else with sharp edges and flat color - or if you genuinely need pixel-perfect, lossless quality - PNG's larger file size is a reasonable tradeoff. The issue is specifically when a photo ends up saved as PNG by default; that's the case where switching formats helps far more than compressing within PNG ever will.
Frequently asked questions
Why is a PNG so much bigger than a JPG of the same image?
PNG uses lossless compression, which preserves every pixel exactly. That's ideal for graphics with flat color and sharp edges, but far less efficient than JPG's lossy compression when the image is a photo with lots of subtle color variation.
Can I compress a PNG without losing any quality?
To a point, yes - lossless PNG compression can reduce file size somewhat by optimizing how the data is encoded, and reducing the color palette helps too. But a photo saved as PNG will still be far larger than the same photo as JPG or WebP, regardless of how well it's compressed.
What's the actual fix if a PNG is too big to upload?
If the image doesn't need transparency or pixel-perfect lossless quality - which most photos don't - converting it to JPG or WebP will shrink it dramatically more than compressing the PNG itself ever could.