+* `minetest.colorspec_to_colorstring(colorspec)`: Converts a ColorSpec to a
+ ColorString. If the ColorSpec is invalid, returns `nil`.
+ * `colorspec`: The ColorSpec to convert
+* `minetest.colorspec_to_bytes(colorspec)`: Converts a ColorSpec to a raw
+ string of four bytes in an RGBA layout, returned as a string.
+ * `colorspec`: The ColorSpec to convert
+* `minetest.encode_png(width, height, data, [compression])`: Encode a PNG
+ image and return it in string form.
+ * `width`: Width of the image
+ * `height`: Height of the image
+ * `data`: Image data, one of:
+ * array table of ColorSpec, length must be width*height
+ * string with raw RGBA pixels, length must be width*height*4
+ * `compression`: Optional zlib compression level, number in range 0 to 9.
+ The data is one-dimensional, starting in the upper left corner of the image
+ and laid out in scanlines going from left to right, then top to bottom.
+ Please note that it's not safe to use string.char to generate raw data,
+ use `colorspec_to_bytes` to generate raw RGBA values in a predictable way.
+ The resulting PNG image is always 32-bit. Palettes are not supported at the moment.
+ You may use this to procedurally generate textures during server init.