Why was Mary Surratt not photographed after her arrest?

[Eva Elisabeth]

Whatever Mary Surratt knew, I can't believe she was totally unaware. She must at least have sensed something seriously criminal was going on. What was/were her motive(s) to serve as "the keeper of the nest hatched the egg"? Did she do it for her son? Or because she admired Booth as a famous actor or because of his "womanizer qualities" (she had his photo hidden in her room - yes, not only his photo, but...)? Or for the "cause"? Was she just too "weak" to say "No"? Did she expect she would not be sentenced too severe for her part in it? Thanks for any comment!