Add revamped Volcano background.
Replaced stars to better match original design.
Replaced ground lava planes with stylised cracks.
Reworked distant mountains.
Removed extraneous images.

Compress Volcano PNG images.
Compressed with Synopsis:
    optipng [options] files ...
Files:
    Image files of type: PNG, BMP, GIF, PNM or TIFF
Basic options:
    -?, -h, -help	show the extended help
    -o <level>		optimization level (0-7)		[default: 2]
    -v			run in verbose mode / show copyright and version info
Examples:
    optipng file.png						(default speed)
    optipng -o5 file.png					(slow)
    optipng -o7 file.png					(very slow)
Type "optipng -h" for extended help.

Remove alpha channel from Volcano background image.

Tweak floor cracks in Volcano background.

Removed centre crack.

Updated Volcano background to match new stuff.

Removed centre crack image.