Why would she keep the photo in her phone?

So a girl was liking my boyfriends pictures. I texted and told her to stop and she replied and said that my boyfriend was her love. I asked her 4 times for evidence that my boyfriend was her "Love" and she never sent anything. She just kept saying that I was lying. I asked her many times for proof and evidence and she never sent anything. I sent her a picture of me and him together to prove he was my boyfriend and I texted her and told her to leave him alone and she never texted back. She just seen the message. However 9 months later she texted me and was trying to bully me on social media and she started making up lies about me and I found out that she still had the photo of me and my boyfriend in her phone. Why would she keep a photo of me and my boyfriend in her phone for 9 months?
Why would she keep the photo in her phone?
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