This massive image modification removes colour profile information and adds an alpha channel.
The first saves a little space, the second costs a little space. First is needed since SDL on OSX applies colour profile info which, while cool, is useless so long as the other theme colours are un-adjusted. Second is since we are apparently requiring full 32 bit surfaces now.
install(FILES
map.png
map.cfg
preview.png
DESTINATION ${SHAREPATH}Data/Maps/Hedgewars)