Image::Info doesn't download images from URLs, it only supports local files. so you're probably going to get a height and width of zero. Ofcourse you could have tested for that yourself (from the docs):

 my $info = image_info("image.jpg");
 if (my $error = $info->{error}) {
     die "Can't parse image info: $error\n";
 }
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See also LWP::Simple