I have added the image for UPC-E barcodes
Adding UPC-E image
So yeah - looks good apart from a few coding style bits - your IDE is set to 2 space soft tab or something?
phpcs is "PHP_CodeSniffer", and it's a pretty handy tool.
fixing up the code a bit to match phpcs standards
ok I updated the file.
oh, and yes I only added a upc-e example, everything else is the same.