file_scan_directory - case insensitive scans

a trivial thing, but it caused me an hour searching:

thi suse of the function file_scan_directory() found only those files with lower case ending:

$contenido1 = file_scan_directory(
    variable_get('slideshowcs_folderpath', $defaultpath),
    "jpg$|png$|gif$",
    array('.', '..', 'CVS'),
    0, // Callback (0 for no callback).
    FALSE,
    'filename',
    0
    ) ;

I think upperCase / lowerCase should be ignored in file_scan_directory().

I helped myself with hacking this into the module:

"jpg$|png$|gif$|JPG$|PNG$|GIF$",

but that is no solution. actually i can only use lowercase file names with this module ):