  We present a quantitative measure of the internal color dispersion within
galaxies, which quantifies differences in morphology as a function of
wavelength. We apply this statistic to a local galaxy sample with archival
images at 1500 and 2500 Angstroms from the Ultraviolet Imaging Telescope, and
ground-based B-band observations to investigate how the color dispersion
relates to global galaxy properties. The intenal color dispersion generally
correlates with transformations in galaxy morphology as a function of
wavelength, i.e., it quantifies the morphological K-correction. Mid-type spiral
galaxies exhibit the highest dispersion in their internal colors, which stems
from differences in the bulge, disk, and spiral-arm components. Irregulars and
late-type spirals show moderate internal color dispersion, which implies that
young stars generally dominate the colors. Ellipticals, lenticulars, and
early-type spirals generally have low or negligible internal color dispersion,
which indicates that the stars contributing to the UV-to-optical emission have
a very homogeneous distribution. We discuss the application of the internal
color dispersion to high-redshift galaxies in deep, Hubble Space Telescope
images. By simulating local galaxies at cosmological distances, many of the
galaxies have luminosities that are sufficiently bright at rest--frame optical
wavelengths to be detected within the limits of the currently deepest
near-infrared surveys even with no evolution. Under assumptions that the
luminosity and color evolution of the local galaxies conform with the measured
values of high-redshift objects, we show that galaxies' intrinsic internal
color dispersion remains measurable out to z ~ 3.
