  We present the first Swift Ultra-Violet/Optical Telescope (UVOT) gamma-ray
burst (GRB) afterglow catalog. The catalog contains data from over 64,000
independent UVOT image observations of 229 GRBs first detected by Swift, the
High Energy Transient Explorer 2 (HETE2), the INTErnational Gamma-Ray
Astrophysics Laboratory (INTEGRAL), and the Interplanetary Network (IPN). The
catalog covers GRBs occurring during the period from 2005 Jan 17 to 2007 Jun 16
and includes ~86% of the bursts detected by the Swift Burst Alert Telescope
(BAT). The catalog provides detailed burst positional, temporal, and
photometric information extracted from each of the UVOT images. Positions for
bursts detected at the 3-sigma-level are provided with a nominal accuracy,
relative to the USNO-B1 catalog, of ~0.25 arcseconds. Photometry for each burst
is given in three UV bands, three optical bands, and a 'white' or open filter.
Upper limits for magnitudes are reported for sources detected below 3-sigma.
General properties of the burst sample and light curves, including the
filter-dependent temporal slopes, are also provided. The majority of the UVOT
light curves, for bursts detected at the 3-sigma-level, can be fit by a single
power-law, with a median temporal slope (alpha) of 0.96, beginning several
hundred seconds after the burst trigger and ending at ~1x10^5 s. The median
UVOT v-band (~5500 Angstroms) magnitude at 2000 s for a sample of "well"
detected bursts is 18.02. The UVOT flux interpolated to 2000 s after the burst,
shows relatively strong correlations with both the prompt Swift BAT fluence,
and the Swift X-ray flux at 11 hours after the trigger.
