  Nuclear charge radius differences in the silver isotopic chain have been
reported through different combinations of experiment and theory, exhibiting a
tension of two combined standard errors. This study investigates this issue by
combining high-accuracy calculations for six low-lying states of atomic silver
with an improved measurement of the $5s ^2S_{1/2} - 5p ^2P_{3/2}$ transition
optical isotope shift. Our calculations predict measured electronic transition
energies in Ag I at the 0.3\% level, the highest accuracy achieved in this
system so far. We calculate electronic isotope shift factors by employing
analytical response relativistic coupled-cluster theory, and find that a
consistent charge radius difference between $^{107,109}$Ag is returned when
combining our calculations with the available optical isotope shift
measurements. We therefore recommend an improved value for the mean-squared
charge radius difference between $^{107}$Ag and $^{109}$Ag as $0.207(3)[4]$
fm$^2$, within one combined error from the value derived from muonic Ag
experiments, and an updated set of charge radii differences across the isotopic
chain.
