Here's how I would do it: 1. Read in the whole HTML file into a variable:

open FILE,"filename";
read FILE,$file,100000;
close FILE;
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(I've seen few HTML docs that are over 100000 bytes in size)
2. Split the $file by "<IMG":

@lines = split(/\<IMG/,$file);
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3. Shift out the first line of @lines (it doesn't have an <IMG> tag in it, so we don't need it) and begin to create the new HTML file

$newfile = shift @lines;
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4. For each line in @lines:
Split the line at the first ">"
Replace the "SRC=" element with the new "SRC=" element, assuming that the new graphic is based on the old graphic's URL

foreach $line (@lines) {
  $pos = index($line,'>');
  $tag = substr($line,0,$pos+1);
  $restofline = substr($line,$pos+1);
  $tag =~ s/SRC\=\"(.*?)\"/SRC\=\"$newurls{$1}\"/gi;
  $newfile .= $tag . $restofline . "\n";
}
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5. Do whatever with the $newfile:

print $newfile;
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Complete code: open FILE,"filename"; read FILE,$file,100000; close FILE; @lines = split(/\<IMG/,$file); $newfile = shift @lines; foreach $line (@lines) { $pos = index($line,'>'); $tag = substr($line,0,$pos+1); $restofline = substr($line,$pos+1); $tag =~ s/SRC\=\"(.*?)\"/SRC\=\"$newurls{$1}\"/gi; $newfile .= $tag . $restofline . "\n"; } %