BYTETOOLS

PNG-24 to PNG-8 Converter

Shrink a 24-bit PNG by quantising it to a 256-colour indexed palette with optional Floyd-Steinberg dithering, and see the byte saving live.

Drop a 24-bit PNG to convert to an 8-bit indexed PNGQuantised and re-encoded in your browser — the file is never uploaded

A PNG-8 stores a palette of up to 256 colours plus one index per pixel, which is far smaller than three bytes per pixel. Choose an image and pick how many colours to keep.

What is the PNG-24 to PNG-8 Converter?

A PNG-24 stores three bytes of colour for every pixel. A PNG-8 stores a palette of up to 256 colours once and then a single index per pixel, which is why flat illustrations, logos, screenshots and UI graphics often drop to a third of their original size with no visible change at all.

  • Median-cut palette of 2 to 256 colours with a live size comparison
  • Optional Floyd-Steinberg dithering to keep gradients smooth
  • Binary transparency kept as a tRNS palette entry, exactly like a GIF's transparent index
  • Indexed PNG written by hand with IHDR, PLTE, tRNS and a CRC-stamped IDAT
  • Side-by-side original and quantised preview before you commit
  • Entirely local — the image never leaves your browser

How to use the PNG-24 to PNG-8 Converter

  1. 1

    Drop a PNG, JPG or WebP onto the upload area.

  2. 2

    Drag the maximum colours slider — 256 is safest, and lower numbers shrink the file further.

  3. 3

    Choose whether to keep transparency as a single transparent palette slot, or flatten it onto a colour.

  4. 4

    Leave Floyd-Steinberg dithering on for photos and gradients; turn it off for flat graphics and pixel art.

  5. 5

    Click Convert to PNG-8, compare the two previews, then download the result.

About the PNG-24 to PNG-8 Converter

A PNG-24 stores three bytes of colour for every pixel. A PNG-8 stores a palette of up to 256 colours once and then a single index per pixel, which is why flat illustrations, logos, screenshots and UI graphics often drop to a third of their original size with no visible change at all.

The palette is built with median cut: the tool puts every sampled colour in one box, repeatedly splits the box with the widest colour range at its median, and averages each final box into a palette entry. Floyd-Steinberg dithering then spreads the leftover error into neighbouring pixels, which keeps gradients and skies smooth instead of banded.

The output is written by hand rather than handed to the browser: an IHDR with colour type 3, a PLTE palette, a tRNS chunk when transparency is in play, and a deflate-compressed IDAT, each with its own CRC-32. It all happens locally in your browser, so the image is never uploaded and you can compare before and after side by side before downloading.

Frequently asked questions

What is the difference between PNG-8 and PNG-24?

PNG-24 stores a full 16.7 million-colour value for every pixel, while PNG-8 stores a palette of at most 256 colours plus one small index per pixel. PNG-8 files are much smaller, which is why they suit logos, icons and flat graphics.

Does converting to PNG-8 lose quality?

It can, because colours outside the 256-entry palette have to be approximated. Flat artwork usually looks identical, while photographs show some banding — turning on dithering hides most of it by trading a little noise for smoother transitions.

Can a PNG-8 file have transparency?

Yes, but only on or off per palette entry rather than a smooth alpha channel. This tool reserves one palette slot for fully transparent pixels and writes it into the tRNS chunk, which is the same approach GIF uses.

How much smaller will my PNG get?

It depends entirely on the picture. Screenshots and flat illustrations often drop by 50 to 70 percent, while photographs may barely shrink. The change percentage is shown next to the original and new file size after every conversion.

Should I use dithering?

Use it for photos, gradients and anything with soft shading, because it prevents visible bands. Turn it off for logos, line art and pixel art, where dithering adds speckle and often makes the file slightly bigger.

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