Snagit Editor: Use PNG-8 to reduce file size

For images meant for the internet, it is very important to keep the file sizes as small as possible. This often makes PNG-8 a better option than Snagit’s default PNG-24.

Why PNG-8?

The 8 in PNG-8 refers to the number of bits used to store color information. With 8 bits we get only 256 colors but the file sizes are much smaller. At first glance, this compares very poorly with PNG-24 which supports millions of colors. But each PNG-8 file has a color index attached to it. This allows PNG-8 to support all the colors that PNG-24 supports, as long as the number of colors in a single image does not exceed 256. PNG-8 format gives poor quality if there are a large number of colors in a single image. But I have never come across such images among my Snagit captures. Your experience might be different, especially if you are editing external images. Here is a comparison between the two formats.

PNG24 Sample
PNG-24 [size=17.1KB]
PNG8 Sample
PNG8 [size=8.39KB]

To me, both images look the same while one is only about half the size of the other. This is not surprising because according to Faststone Image Viewer the image has only 199 colors. For any image with less than 256 colors, PNG24 is a waste of space. Even if the image has more than 256 colors, Snagit Editor will do some lossy filtering to bring the number of colors down to 256. Lossy filtering is not recommended for serious artwork but works fine for most of the Snagit captures.

How to save as PNG-8 in Snagit Editor

  • Click the Save As option from the File menu. The Save option works as well as long as you have not already saved it in a different format.
  • Click the Options button.
  • Choose 256 colors (8-bit) in the colors dropdown.
  • Click OK.
  • Save the file as usual.

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