Whether or not she would be sent to prison is left up to the viewer's imagination.
1) Why would she kill that lady after being told not guilty KNOWING the media & cops are there to catch her now?
Beverly was a sociopath--egocentrics and they have no remorse, no guilt and no empathy--along with other types of crazy. She also beat Ms. Ackerman to death (with the leg of lamb, LOL) and burned that kid alive all whilst on the run from the authorities.
2) Why was she so upset at Suzanne for wanting to pose in a picture?
Again--she was bat-sh!t crazy. It's the same reason why she would kill a woman for wearing white after Labor Day.
---------------------------------------- "It's like my daddy use to always say..."
While I understood she was bat crazy, she was smart enough to pose as her own attorney during the court scenes & trick each of the witnesses to make her look good in front of the jury (ala making the one lady curse, making Beverly admit she doesn't recycle, making the one guy so horny he confessed). So it makes me wonder a bit.
True, she was smart and calculating but, many nut-jobs are. Remember the Harvard professor who lost it?
I'm not a psych major so, I could be wrong about Beverly's specific diagnosis. But, from what I've read--most serial killers are psychopaths (Manson) and/or sociopaths (Gacy, Dahmer). Either way, they tend to be pretty intelligent.
---------------------------------------- "It's like my daddy use to always say..."
2) Why was she so upset at Suzanne for wanting to pose in a picture? Confusing as hell. Can anyone explain.
It wasn't the posing itself that annoyed her, it was the fact that Suzanne was bossing her around and being rude in general. The (original) script makes it more clear:
FARRAH FAWCETT barges in and takes over.
FARRAH Hello, Beverly. I'm Farrah Fawcett (Pulling MOM rudely) You stand here... (To PRESS) Ok, boys, a medium two shot...
MOM (Trying to get on other side of FAWCETT) ...but please...if I could just...
FARRAH (Rudely shoving MOM back in place) Stay there, Beverly. (Posing) Smile, Serial Mom!
Flashbulbs explode.
MOM (Hissing to FARRAH in the scariest, most threatening voice yet) THAT'S MY BAD SIDE, FARRAH FAWCETT!!
1) Wouldn't it be double jeopardy to put her on trial for the same thing again?
2) I believe if you listen to what she's saying to Suzanne Somers before that, i believe she's trying to tell her she'd rather stand on the other side of her for the photo to show her "good side"