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.
Remember, after making a claim months ago that he attacked her in February, she recanted on the stand saying she made up the allegations in a fit of anger after being dumped.
And, it got even worse when she appeared on 'GMA' and said she lied about lying on the stand.
Bottom line ... seems prosecutors realize there is no way they could prove guilt beyond a reasonable doubt with an alleged victim who has repeatedly lied about the very thing for which Foster was arrested.
8:51 AM PT -- An NFL spokesperson tells TMZ Sports ... "We are monitoring all developments in the matter which continues to be under review by the league."
7:22 AM PT -- TMZ Sports spoke with Foster's attorney Eddie Suarez who tells us he believes the case was dropped due to issues with the witness' credibility.
Suarez says he believes the fact Foster's accuser has changed her story about a previous domestic violence incident multiple times was a factor in the decision to drop the case.
Reuben Foster is off the hook in his domestic violence case ... again.
TMZ Sports has obtained a court document filed on Jan. 2 which shows the State Attorney's Office in Florida has dismissed the misdemeanor charge against Foster stemming from a Nov. 24 incident with his ex-girlfriend.
Foster was scheduled to appear at an arraignment in Hillsborough County, FL on Thursday morning -- but the hearing was canceled after the notice of termination of prosecution was filed.
Unclear why prosecutors decided to drop the case against the 24-year-old linebacker -- we've got calls out to everyone.
As we previously reported ... Foster was arrested back on Nov. 24 for allegedly roughing up his ex-GF, Elissa Ennis, at the 49ers' team hotel in Tampa Bay.
Ennis said in an interview with "Good Morning America" on Dec. 6 the fight stemmed from her threatening to tell Foster's new GF that he paid for her flight out to Florida.
In 911 audio obtained by TMZ Sports ... Ennis says, "My ex-boyfriend just took my phone [and broke it] ... slapped me in my face and threatened me."
She later repeated, "He took my phone and broke it and slapped me in my face."
Ennis said on 'GMA' that wasn't the first time Foster had struck her ... saying he had also roughed her up on two other separate occasions -- one of which she says she lied about in court to protect the LB.