  We revisit the analysis of sharp infinite potentials within the path integral
formalism using the image method [1]. We show that the use of a complete set of
energy eigenstates that satisfy the boundary conditions of an infinite wall
precisely generates the propagator proposed in Ref. [1]. We then show the
validity of the image method by using supersymmetric quantum mechanics to
relate a potential without a sharp boundary to the infinite square well and
derive its propagator with an infinite number of image charges. Finally, we
show that the image method readily generates the propagator for the
half-harmonic oscillator, a potential that has a sharp infinite boundary at the
origin and a quadratic potential in the allowed region, and leads to the well
known eigenvalues and eigenfunctions.
