Depends: was this photo taken after recently driving it (a couple hours or less)?
if so, might be a touch low but definitely not something I’d run out and refill especially if you have an oil change coming up relatively soon.
if the engine was completely col, you are golden.
that bulb is an overflow tank and gives (read: requires) there to be space for the coolant to expand when it heats up. It should NOT be anywhere over that half way mark when cold.
(officially,to be proper it should be at the little mold mark in the bulb when cold…but if it’s sitting a little below that it’s fine and won’t hurt anything)