Strangely, this same problem started happening to me this morning ... after months of no problems. I am certain that I haven't made any remotely-related changes in the past few days.
Anyway, here is an easier solution that worked for me.
Instead of trying to change the pic from the address book app, I went into the system preferences screen "Users & Groups". (If locked, unlock the page to make changes.) Click on the picture and select "Edit Picture". At the top select "Recent Pictures" and select the one you want. Then click "Set".
Within a second or two, the address book picture changed to my desired picture. No problems since.