1:24 PM PT -- TMZ Sports has obtained the injury photos of Elissa Ennis -- the woman who claims Foster attacked her ... but apparently the pics weren't compelling enough for charges to be pursued.
You can see a big red bruise on her cheek and red marks on her chest.
The photos were taken in the aftermath of the Nov. 24 incident -- the woman claims Foster hit her in the face while trying to take her cell phone. She called 911 and cops responded to the team hotel.
Foster's attorney tells us he believes prosecutors dropped the case because of credibility issues.