  We present a sample of microlensing events discovered in the Difference Image
Analysis (DIA) of the OGLE-II images collected during 3 observing seasons,
1997--1999. 4424 light curves pass our criteria on the presence of a
brightening episode on top of a constant baseline. Among those, 512 candidate
microlensing events were selected visually. We designed an automated procedure,
which unambiguously selects up to 237 best events. Including 8 candidate events
recovered by other means, a total of 520 light curves are presented in this
work.
  In addition to microlensing events, the larger sample contains certain types
of transients, but is also strongly contaminated by artifacts. All 4424 light
curves in the weakly filtered group are available electronically, with the
intent of showing the gray zone between microlensing events and variable stars,
as well as artifacts, to some extent inevitable in massive data reductions. We
welcome suggestions for improving the selection process before the full
analysis of complete 4 seasons of the OGLE-II bulge data. Selection criteria
for binary events can also be investigated with our extended sample.
