VFDs are indicated at 380v - 480v so unlikely they can also run at 240v - at least not supported by the label.
Also its not that easy, you can easily change motor wires - but then you need to deal with all magnetic switches for each motor. These may or may not have the amp range and may have coil voltage of 400v or some control voltage. If control voltage you need to make sure control transformer has the right taps. It looks like there is a transformer that supports 230v and 400v - but not sure what it controls. Sometimes these guys control other electronics not magnetic switches coils. I.e. it all needs to be looked at whatever you can run at other voltage.
I see what your saying, i think a guy needs to look at every option before spending the bucks. None of us can say for sure with the information provided what the best course of action is, maybe everything in that box is capable of 230 and he can just re-wire the motors, maybe not, I do see that the 24v transformer is rated for 230, so that leave the mag switch and the vfd's
But maybe new vfd's (if reqd) is more costly than a transformer, and assuming they are ok with a transformer that's the way to go
Sometimes guys will spend extra to not run a transformer, orders of magnitude extra (hello Calgary airport)
The op should consider the options, talk with his boss, and come up with a game plan