Hello,
There are a few different scanarios that could be perceived as approving a voucher - batch approval, payee approval or via workflow as a minimum. Which form of approval or you using?
Also, if you attach an image to a voucher JDE will add a record to the F00165 which is linked to the voucher via the generic text key, GDTXKY and object name. The link is established to the specific voucher line via one of the F0411 key fields separated by the "|" character - DOCO|DCT|DOC|SFX - example: 02000|PV|59|001 where GDOBNM = GT0411S. There's probably other ways to attach images that might get a different GDOBNM or GDTXKY but that is the most basic way to do it.