These are 24-bit BMP files with 16.7 million colors.  They are intended for
screens which are at least 800x600 pixels.  It would not be difficult to
convert the files to 8-bit BMP files.

These BMP tiles were created with Fractal Weave and captured with PCXDUMP.
The final images were cut from the PCX files using PaintShop.

These tiles make absolutely lovely backgrounds for Windows.