Unfortunately, I do not see it mentioned anywhere in the documentation and I am not sure how to set it up.
This is because it has been made possible and Vifm now provides means to achieve it, but that's where support ends, i.e. nothing is hard-coded and theoretically any similar application might work by using these means.
There is related Wiki page describing possible setup with
w3mimgdisplay: How to preview images.
It's worth noting that ranger supports displaying full color images on *NIX and even on OS X (iTerm).
As far as I know it also uses
w3mimgdisplay, although not sure about OS X.
In case of
ranger it is more hard-coded and thus somewhat more convenient to users, but not very good from design point of view (unfortunately, what's good for application sometimes leads to worse user experience, but I think consistency of application should be preserved, unless there are strong reasons to break it).