  We analyze HST+WFPC2 images of 77 early-type galaxies. Brightness profiles
are classed into "core" or "power-law" forms. Cores are typically rounder than
power-law galaxies. Nearly all power-laws with central ellipticity >=0.3 have
stellar disks, implying that disks are present in power-laws with epsilon <0.3,
but are not visible due to unfavorable geometry. A few low-luminosity core
galaxies also have disks; these may be transition forms from power-laws. Cores
and power-laws both have twisting isophotes at small radii. Core galaxies have
somewhat weaker color gradients than power-laws. Nuclei are found in 29% of the
cores and 60% of the power-laws. Nuclei are typically bluer than the
surrounding galaxy. NGC 4073 and 4382 have central minima in their intrinsic
starlight distributions; NGC 4382 resembles the double nucleus of M31. In
general, the peak brightness location is coincident with the photocenter of the
core to <1 pc. Five galaxies, however, have centers significantly displaced
from their cores; these may be unresolved asymmetric double nuclei. Central
dust is visible in half of the galaxies. The presence and strength of dust
correlates with nuclear emission. The prevalence of dust and its morphology
suggests that dust clouds form, settle to the center, and disappear repeatedly
on ~10^8 yr timescales. We discuss the hypothesis that cores are created by the
decay of a massive black hole binary. Apart from their brightness profiles,
there are no strong differences between cores and power-laws that demand this
scenario; however, the rounder shapes of cores, their lack of disks, and their
reduced color gradients may be consistent with it.
