Clumps of just anti-matter will have the same gravity field around them as clumps of matter.
There was an experiment at either Fermilab or SLAC in the 1970s or early 1980s where the falling of a beam of anti-protons was measured. I was trying to look up details on this a couple years ago, and didn't find it. But I know I read about it long ago. Bottom line: anti-protons fell just the same as protons. (It might have been neutrons and anti-neutrons, not sure.) The curvature of spacetime guides antimatter and matter alike. Just as an expert shooter must aim the gun a wee bit high to account for gravity pulling the fired bullet down, so too must physicists account for the falling of electron beams, positron beams, proton or antiproton beams, pion beams, etc. Except in practice, it's ignored due to the short flight time and small compared to imperfections of strong magnetic fields and whatnot.
As for the field of gravitational acceleration surrounding anti-protons or other anti particles - this cannot be measured, even for regular matter. Only for "big" things like planets, asteroids, or even balls of lead in laboratories, can the field due to the matter be measured. We've never made or found anything bigger than an atom made of anti-matter.
The photon is neither matter nor anti-matter. It is its own opposite. When interacting with matter or antimatter, all it cares about is + or - charge. If there's anything like an anti-photon, it's when a coherent beam is shifted by 180 degrees - waves canceling as in an interferometer.