This is an 8-bit (8bpp) image set.

Many images are automatically generated. All 8-bit images are generated from RGB or RGBA (32bpp) png images.
The 32bpp png images may themselves have a source, and may be manually derived from Paint.NET (pdn), GIMP (xcf) or Blender (blend) files.

All "*_8bpp.png" and "*_bt32bpp.png" images are automatically generated from the file called "*_32bpp.png".
Do not directly modify any file named "*_8bpp.png" or "*_bt32bpp.png", your changes will be overwritten!

Files within a directory named "pygen" are automatically generated from images in the parent directory.
This includes files named "*_32bpp.png", do not modify them as your changes will be overwritten!

NB. The "*_32bpp.png" images may not actually be RGB or RGBA, but their name indicates they should be handled as 32bpp source images.

Typically, sprites are generated by:
Either, for buildings:
	Taking an object shape from a file named "*_shape.png" and recolouring and texturing it based on specialised pixels on row 1 of the image.
Or, for terrain and infrastructure tiles:
	Taking a base texture from a reference "*_32bpp.png" file, eg. standard ground grass
Overlaying various additional layers to add detail:
	"*_overlayalpha.png": A 32bpp image overlaid in alpha blending mode.
	"*_overlayshading.png": A 32bpp image overlaid in overlay blending mode.
	"*_overlaynormal.png": A pseudo-8bpp image overlaid in alpha blending mode.
Converting to 8bpp:
	Conversion uses a custom, standardised, dither script, making "*_8bpp.png".
	If "*_palmask.png" exists, restricting dither to within the colour series/groups within this set.
	"*_palmask.png" is usually generated from unshaded recoloured "*_shape.png" images, overlaid with "*_overlaynormal.png"
	Animated palette indices are not used in normal dithering, unless in the "*_palmask.png" image, in which case they are protected and preserved.
Converting for 32bpp:
	Conversion uses two strategies:
	1. Simply replace tranparent blue in the 32bpp image with transparent, making the 'blue transparent' image "_bt32bpp.png". This is good for most sprites.
	2. Make tranparent blue in the 32bpp image transparent, and for other pixels measure the brightness difference to the 8bpp sprite making the 'remainder' image "_rm32bpp.png". This is convenient for recoloured sprites.

Further sprite specific processing may be done, including:
	Overlaying/merging sprites (eg. building sprites onto their ground tile)
	Cutting up a sprite into individual sprites (eg. multi-tile buildings)
	TODO: Ensuring a region of multiple sprites is identical between them (eg. avoiding dither dancing for animations)