  In this work, we investigate the question, whether the conventional analysis
of the electromagnetic form factors of the nucleon, evaluated in the framework
of the cloudy bag model (CBM) or other chirally invariant hybrid quark models
utilizing the same philosophy, is gauge invariant. In order to address that
point, we first formulate the CBM in a style that resembles the technique of
loop integrals. Evaluating the self energy and the electromagnetic form factors
of the nucleon in that manner and comparing with the standard analysis where
nonrelativistic perturbation theory is used, allows us to show that our
approach is appropriate and to point out, what approximations are made in the
standard derivation of the model. {}From the form of those loop integrals, we
then show that additional diagrams are needed to preserve electromagnetic gauge
invariance and we assess the corresponding corrections.
