Like most other FB related sites they do have a limp DCMA Copyright violation form to fill out- https://help.instagr...539946876093520
As usual the onus is on the copyright holder to find and point out violations. The website/host distances itself from any onus to discourage or prevent
such infringements from happening. Same as FB, Pinterset, etc, etc...
Another annoying part of the Instagram reporting process is that they provide your contact details to the infringer.