Jesse James' Ex Janine Lindemulder -- The New Mug Shot

Jesse James' ex Janine Lindemulder was thiiiiiiis close to smiling in her new mug shot -- taken when she was arrested for harassment at her home in Texas yesterday.

Sources tell TMZ ... Janine has called Jesse more than 25 times in the last few days -- and that was enough for cops to get a harassment warrant.

Janine is still in custody -- and is set to face a judge later this morning.