Packing slip logo prints as black rectangle

Hi all,

I followed some steps according to a post on here about adding a logo to our packing slips. Unfortunately when printing the packing slips on our thermal printer, the area around the logo graphic itself (transparent png.) prints as black as well.

Has anyone got any tips for working around this?

I managed to fix the issue. Changing the file from a PNG to JPG seemed to fix it!