Alois, I think you are confusing something that doesn’t have to be complex. If you want to keep them at 96 dpi, that’s okay just don’t make them huge in size. You don’t want to clog someone’s inbox with huge images.
72 dpi is a standard, not a rule. And if this is stopping you from sending in an application then let it go. Make a note to learn more about this subject at the next opportunity. But don’t sweat too much over this detail.