[Improved Support for Indexed Color]

It would be very helpful if Affinity Photo had support for working with indexed/palletized images, if not support for editing in indexed color, at least a fully featured indexed export. The Palettize feature in the current export settings does not [appear to] have an option to supply a specific palette such as from an .act or .pal file and does not have any way to specify the method of dithering as seen in the cursed application I'm trying to replace with a single solution.

Also, when trying to export an image as an indexed .png or .gif using the Palette: Custom setting results in an error 100% of the time: