PNG images can be saved Interlaced. This is useful, if you want to use the image on a web page (see GIF).
Another option is the strength of compression.
By default PhotoLine saves size-optimized PNG files. For this purpose, transparent areas in the image are filled with a uniform color and images with a maximum of 256 colors are saved as palette images. However, there are situations in which this is not desired, so this behaviour can be switched off by Optimize Size.
Furthermore you have the option to automatically reduce the number of colors when saving in the PNG-format. You have also the choice to turn on Ask. In this case on saving the Color-Reduce dialog is shown, otherwise the reduce scheme selected in Preset will be used for reduction (see chapter 5.7.2).