I will see the broken image only with unowns, it is happening when
the egg hatches, on the page where it shows to feed the pokemon and
in auction. Oddly it shows up fine in storage boxes if it isn't in
my party or if it is in my party then I just need to refresh the
page. This happens on pc and mobile.
I am not sure on why this is happening, but you should put this in
the Pokeheroes Broken Pictures thread, where they will be
more noticeable. I hope this is fixed, thanks for your report.