Without looking at the code, I suspect it's because the found routine is being executed in many different current directories in both cases, but add_files is being handed the wrong path for the job in the second case. When you're in foo/bar, you can't open foo/bar/this.jpg, because it almost certainly doesn't exist. You have to open this.jpg.

Modern versions of File::Find can be told not to chdir, but that makes them pretty inefficient, so your first program version is probably the best anyway.

-- Randal L. Schwartz, Perl hacker
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