PNG-24 vs PNG-8: Which Format Cuts File Size Without Killing Quality?
PNG-24 is a true-color format with 16.7 million colors and an 8-bit alpha channel; PNG-8 is a palette format that holds up to 256 colors plus 1-bit transparency. Both are lossless, but the way they store pixels—and therefore file size—differs dramatically.
Designers reach for PNG-24 when they need glassy gradients or drop shadows, then wonder why their hero banner weighs 1 MB. Meanwhile, a PNG-8 export of the same icon often looks identical on mobile yet downloads in a blink. The mix-up happens because “PNG” feels like one thing, not two siblings with very different diets.
Key Differences
PNG-24 stores every pixel’s exact red, green, blue, and alpha values—great for photos, heavy for the wire. PNG-8 keeps a slim 256-color lookup table and reuses each swatch thousands of times, shrinking files up to 80 %. Transparency in PNG-8 is either fully on or off, while PNG-24 offers 256 levels of fade.
Which One Should You Choose?
Use PNG-8 for flat-color logos, UI glyphs, and simple charts where crisp edges matter more than gradients. Reach for PNG-24 only when subtle fades or soft shadows are non-negotiable. When in doubt, export both and let your eyes and file-size meter decide.
Examples and Daily Life
That 32-pixel Twitter bird? PNG-8 at 3 KB looks perfect. Your app’s splash screen with a sunset gradient? PNG-24 keeps the sky smooth at 180 KB. A quick TinyPNG pass can shave another 30 % off either without visual loss.
Does PNG-8 support semi-transparent pixels?
No, transparency is a single on/off switch. Use PNG-24 if you need fades or shadows.
Can I convert PNG-24 to PNG-8 later?
Yes, but complex gradients may band. Test on the target screen before shipping.