The casing issue was fixed in version 1.8, so quite a while ago.
Currently, the pattern that is matched is: one or more numeric digits, followed by a single space, followed by 'mirror' in any combination of casing, then another single space, and then 'image' in any combination of casing.
If you are fluent in regular expressions, this is the pattern being matched: "(%d+) [mM][iI][rR][rR][oO][rR] [iI][mM][aA][gG][eE]". I thought about changing the spaces to "%s+" to make it more flexible, but have not implemented that change as of yet.