Query on Facial Image for Kid for 190 Visa Application

Hi Team,

I understood we need photograph for all the applicants including declaration on back side of photographs.
But what about the kid? Is it necessity to have a signed declaration for kid. She is only 5 years and she won’t be able to sign. Do we have to put her fingerprint on back of the photo or is there any exemption for the kid for the same?
I couldn’t find any details on this. Can someone please guide me.

Thanks in advance.