  We report the results of James Webb Space Telescope/NIRCam observations of 19
(sub)millimeter (submm/mm) sources detected by the Atacama Large Millimeter
Array (ALMA). The accurate ALMA positions allowed unambiguous identifications
of their NIRCam counterparts. Taking gravitational lensing into account, these
represent 16 distinct galaxies in three fields and constitute the largest
sample of its kind to date. The counterparts' spectral energy distributions
from rest-frame ultraviolet to near infrared provide photometric redshifts
($1<z<4.5$) and stellar masses ($M_*>10^{10.5}$ Msol), which are similar to
sub-millimeter galaxy (SMG) hosts studied previously. However, our sample is
fainter in submm/mm than the classic SMG samples are, and our sources exhibit a
wider range of properties. They have dust-embedded star-formation rates as low
as 10 Msol yr$^{-1}$, and the sources populate both the star-forming main
sequence and the quiescent categories. The deep NIRCam data allow us to study
the rest-frame near-IR morphologies. Excluding two multiply imaged systems and
one quasar, the majority of the remaining sources are disk-like and show either
little or no disturbance. This suggests that secular growth is a potential
route for the assembly of high-mass disk galaxies. While a few hosts have large
disks, the majority have small disks (median half-mass radius of 1.6 kpc). At
this time, it is unclear whether this is due to the prevalence of small disks
at these redshifts or some unknown selection effects of deep ALMA observations.
A larger sample of ALMA sources with NIRCam observations will be able to
address this question.
