Thanks for your research!
Looks like imagefap continues its struggle against mass download.
Can not tell exactly when they made the last move -
some years passed since my last use...
Not only f#^%ing Putin forbids me to see funny pictures
(senseless automatic blockings are typical here in Russia,
f. e. imagefap is banned totally / at whole),
but even a site itself prevents us from its content,
forcing a user to make a 10x series of stupid/repeating clicks for 1 picture
instead of a couple for all gallery.
Note, the most disturbing thing
is that I'll not see their ads anyway (thanks to Request Policy),
even if I'll visit all the pages they force me to.
Returning to the problem.
Does I understand right:
it is impossible to guess /full/ picture link (including "secure" tail) from the source of the gallery page,
so it is necessary to ask/receive each individual picture page
to extract the embedded actual /full/ link from "contentUrl"?
Same function like HTTrack Website Copier, Teleport Pro or the same, set to depth/digging level 2
with mask equal to DOS's "https://cdn.imagefap.com/images/full/