Slashes in png generation are mis-placed. They do not show up in the wrong position on the original PDF. The are offset by many pixels to the right in the png that is generated.
I simply exported with this command:
java -jar pdfbox-app-1.8.2.jar PDFToImage -imageType png -resolution 300 -color bilevel pdfbox_test2.pdf
Unfortunately I can't use PDFBox to export PDF to image if it doesn't place the characters in the right place.