How can you add the item picture in a custom packing slip?

Original post by user Miguel Adler

I'd like to print the picture of the item in the packing slip, to help packers insure they are packing the right thing.

Pictures of the items appear in the pick list, so I know its available, but when customizing the packing slips, there does not seem to be an option, other than displaying the link.

(I do not know HTML)