writefile("imgconversions.mdwn", "t/tmp/in", <<EOF
[[!img redsquare.png]]
[[!img redsquare.png size=10x]]
[[!img redsquare.png size=30x50]] expecting 30x30
writefile("imgconversions.mdwn", "t/tmp/in", <<EOF
[[!img redsquare.png]]
[[!img redsquare.png size=10x]]
[[!img redsquare.png size=30x50]] expecting 30x30