I'm positive there is an audience for men's feet, but if you aren't 5 stars on wikifeet, you'll probably have to market yourself. Study the foot fetish community to find out what the dude foot fan needs more of. Etc.
Hmmm...the problem is, even if you just post pictures at random, you're going to find out unwanted info based on what pics bring in money. Sounds like you'd need a manager!
I often joke that I’m the person happiest that malls have died off because as a kid I was always forced to go there and try on a a bunch of 12s and 13s that never fit.
These days I’m still upset that so many good looking shoes only go up to 13