They won't interfere but maybe won't work optimally. If no sex in the path/name then it assumes female. If no age, it assumes adult. Doesn't have to have tags for hair, skin, tits, or ass. Just an image that does match those will much more likely be selected (it's fuzzy when it comes to those last 4). Might want to leave it in if you have an existing game and characters already set to those portraits that you don't want to change? Otherwise, the pack I linked above includes all of LeLurker's , Butler's, Scars Unseen, and AK|Phantom's packs, plus a ton more, so only keep the old if you want existing slaves to keep using their current portrait.
There's also a tool I linked in previous post which can let you rename existing portraits with tags (displays the portrait, and matching body if it exists, and shows detected tags, lets you add/change/remove tags and then "apply" to rename). Could use that with basically any portrait pack to make it work better with the mod.
