  Continuum emission, also called white-light emission (WLE), and permanent
changes of the magnetic field ($\Delta{B}_{{\rm{LOS}}}$) are often observed
during solar flares. But their relation and their precise mechanisms are still
unknown. We study statistically the relationship between
$\Delta{B}_{{\rm{LOS}}}$ and WLE during 75 solar flares of different strengths
and locations on the solar disk. We analyze SDO/HMI data and determine for each
pixel in each flare if it exhibited WLE and/or $\Delta{B}_{{\rm{LOS}}}$. We
then investigate the occurrence, strength, and spatial size of the WLE, its
dependence on flare energy, and its correlation to the occurrence of
$\Delta{B}_{{\rm{LOS}}}$. We detected WLE in 44/75 flares and
$\Delta{B}_{{\rm{LOS}}}$ in 59/75 flares. We find that WLE and
$\Delta{B}_{{\rm{LOS}}}$ are related, and their locations often overlap between
0-60\%. Not all locations coincide, thus potentially indicating differences in
their origin. We find that the WL area is related to the flare class by a power
law and extend the findings of previous studies, that the WLE is related to the
flare class by a power law, to also be valid for C-class flares. To compare
unresolved (Sun-as-a-star) WL measurements to our data, we derive a method to
calculate temperatures and areas of such data under the black-body assumption.
The calculated unresolved WLE areas improve, but still differ to the resolved
flaring area by about a factor of 5-10 (previously 10-20), which could be
explained by various physical or instrumental causes. This method could also be
applied to stellar flares to determine their temperatures and areas
independently.
