  We consider the effects of photon diffusion on the small-angle microwave
background anisotropies due to active source models. We find that fluctuations
created just before the time of last scattering allow anisotropy to be created
on scales much smaller than allowed by standard Silk damping. Using simple
models for string and texture structure functions as examples, we illustrate
the differences in the angular power spectrum at scales of order a few
arcminutes. In particular, we find that the Doppler peak heights are modified
by 10-50% and the small-angle fall-off is power law rather than exponential.
