Batch pdf generation with image fails

[atrandafir]

Hello,

There is a bug in the version of dompdf that this bundle uses that causes broken images if you try to generate multiple pdfs containing the same image. (for example, to include them in a zip file).

You can read here about the issue:
https://code.google.com/p/dompdf/issues/detail?id=17
https://groups.google.com/forum/#!topic/dompdf/7perv5jGKvs

Looks like they have fixed it, as this code shows:
https://github.com/dompdf/dompdf/blob/master/include/image_cache.cls.php#L151

But the code here has not been updated. I suggest either update code or manually apply fix.