The saddest memory

This is a photo that contains the saddest memory for me.

I took this photo of the sky during a history tour with my friends. After taking the photo, I felt very satisfied because it made me feel very comfortable and relaxing . But only 15 minutes after taking the picture I received the news that my best friend had passed away due to a traffic accident. She is a pretty girl, smiling, optimistic, and always brings positive energy to everyone around her.
The sky inside me then was very dark as if it was about to collapse.
We made a lot of promises, planned a lot, but now I am the only one to carry out those plans.
I wondered a lot if I should keep or delete this photo because if I keep it, it makes me sad and miss her so much but if I delete it, I'm afraid I'll forget her .