+ # On MacOS 10.3, "screencapture -x" always wrote a PDF.
+ # On 10.4.2, it writes a PNG by default, and the output format can be
+ # changed with the new "-t" argument.
+ #
+ # So, for maximal compatibility, we run it without "-t", but look at
+ # the first few bytes to see if it's a PDF, and if it is, convert it
+ # to a JPEG first. Otherwise, we assume that whatever screencapture
+ # wrote is a file format that xscreensaver-getimage-file can already
+ # cope with (though it will have the extension ".pdf", regardless of
+ # what is actually in the file).
+ #
+ my $pdf_p = 0;