How to use the PNG Compressor
- Drop the PNG files in: screen captures, lower thirds, channel logos or graphics exported from a design app.
- Keep Reduce PNG colours ticked for the largest saving, or untick it when every pixel has to stay identical.
- Under More settings, adjust the palette size or the Effort level if you want to fine-tune.
- Compress, check the size column, and save the files or a ZIP.
Palette mode: the big cut
A typical PNG stores each pixel as full truecolour, even when the image only uses a few hundred distinct shades. Palette mode picks up to 256 colours that represent the picture and stores every pixel as a single index into that list, which commonly removes half to four fifths of the file.
Interface captures, flat logos and text overlays come through looking the same. Soft gradients, glows and photographic areas are where you may notice slight banding; raise the palette size toward 256 or switch the reduction off for those.
Exact mode with OxiPNG
With the box unticked, OxiPNG rewrites the file using better filters and deflate settings and drops channels the picture does not use, such as an alpha channel that is completely opaque. The pixels do not change at all.
Effort decides how many strategies are tried. Higher settings take longer and sometimes find a few more percent; the default of 4 is a sensible middle.
Questions
Will transparent overlays stay transparent?
Yes. Both modes keep the alpha channel, and palette mode includes transparent shades in its colour list.
What happens if a PNG cannot be made smaller?
If the result is not smaller and you did not resize, the original file is returned unchanged.
Should video overlays stay PNG?
Yes, if they need a see-through background in your editor. A compressed PNG keeps that, while a JPG would fill it with a solid colour.
Is there a limit on how many files I can add?
No. Your browser works through them in small parallel groups, however many you drop.