No Perl solution, but even better for maximizing the browser's real estate: put every single image into a
<div style="float:left;..."> element and the images will flow left-to-right, top-to-bottom in the visible browser area.

<div style="float:left;padding:8px;">
  <img src="yadda..." alt="Nice pic" />
</div>
[download]

Just my $0.02...

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Cheers, Joe