I believe you've misunderstood what those methods are supposed to do. That bit of code isn't supposed to allow conversion between different graphical formats, it's supposed to get you from a blob to image data (i.e. you get out the binary data that went in as a blob; it doesn't say it will convert to a different format in the process).

I would assume you want to use convert once you've got the TIFF, but it's not clear from the docs what the Perl hook into that is. You *could* write the file to disk and, since you have the imagemagick stuff installed, spawn a subshell that calls convert:

$image->write('temp.tiff');
system ("/path/to/convert temp.tiff png:newname.png")
 && die "Couldn't convert image";
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( I think you're right to be a little frustrated with those docs, they're not forthcoming on how to use convert in Perl )

perl -e 'print "How sweet does a rose smell? "; chomp ($n = <STDIN>); 
+$rose = "smells sweet to degree $n"; *other_name = *rose; print "$oth
+er_name\n"'
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