  In the framework of Chiral Perturbation Theory including photons, we found
that the contribution of the photon exchange between two intermediate charged
Kaons to the slope parameter of the decay (\eta\rightarrow 3\pi^{0}) amounts to
(-0.0221\pm 0.0034). When compared with the experimental value, (\alpha
=-0.0317\pm 0.0016), on the one hand, and with the contribution of the up and
down quark mass difference, (+0.013\pm 0.032), on the other hand, our result
leads to the direct conclusion: \textit{The} (\eta\rightarrow 3\pi^{0})
\textit{decay \uline{cannot} be used to determine} (m_{d}-m_{u}).
