Enable Images and Tables in RT ticket display

RT: 4.0.19RTIR: 3.0OS: Ubuntu
I’m trying to have tables and images that are copied/pasted in the ticket message displayed when viewing the ticket. The furthest I’ve gotten so far has been to use the Web_Interface.pm module as discussed here: https://bestpractical.com/docs/rt/4.2/RT/Interface/Web.html#NewScrubber
This is letting my table display correctly, unfortuatley without the borders, so seeing when one cell ends and another begins is difficult.
I’ve tried to add IMG to the SCRUBBER_ALLOWED_TAGS, but the image is still not displaying. How can this be done?