Tell Larry Wall thank you ! You can use his rename program:

rename 'my $a=$_ ; 
open XML, "$a.xml"; 
while (my $l=<XML>) 
{ 
if ($l =~ /<rdf:li xml:lang=\"x-default\">(.+?)<\/rdf:li>/) 
{ $a=$1}
} ; close XML; $_=$a' *
[download]

This code suppose about if you have a file named "xx.png", then there are another file named "xx.png.xml" Regards,