  Optical and HI imaging of both dwarf irregular (dI) and Blue Compact Dwarf
(BCD) galaxies reveal important clues on how dwarf galaxies evolve and their
star formation is regulated. Both usually show evidence for stellar and gaseous
disks. However, their total mass is dominated by dark matter. Gas rich dwarfs
form with a range of disk structural properties. These have been arbitrarily
separated them into two classes on the basis of central surface brightness.
Dwarfs with mu_{0}(B) > ~22 mag arcsec^{-2} are usually classified as BCDs,
while those fainter than limit are usually classified as dIs. Both classes
experience bursts of star formation, but with an absolute intensity correlated
with the disk surface brightness. Even in BCDs the bursts typically represent
only a modest < ~1 mag enhancement to the B luminosity of the disk. While
starbursts are observed to power significant galactic winds, the fractional ISM
loss remains modest. Dark matter halos play an important role in determining
dwarf galaxy morphology by setting the equilibrium surface brightness of the
disk.
