Specific OPTIONS for Signatures?

[Kingsguard]

Right now, all I see is a way to turn Signatures ON or OFF.
I'd like to have them on, but not allow images. I'd also like to restrict their length.
Where can I access those setting, please? TIA

[Morrigan]

They are a per group setting:

[Kingsguard]

@Morrigan  Ah, yes! Thank you so much!