$H \to \gamma \gamma$ measurements at the ATLAS experiment

Measurements of the Higgs boson properties at the Large Hadron Collider experiments require a thorough understanding and control of the detector performance. These proceedings describe the reconstruction, identification and calibration of photons at the ATLAS experiment, which are of particular importance for the measurements in the diphoton decay channel. The impact on the property measurements is shown, along with the results of the H→γγ measurements.