Yes, happens to me too time after time,.. some unexpected triggers happen and sometimes certain intensity of grief bubbles up from the depths of memories.. and each time a little dosis of resolution / resignation / resignation settles in.. each time the sad grief turns into “saudade” grief, the warm beautiful nostalgic missing of the dear person who has gone before us.

This happens with my grief for my Mom. Each time it’s triggered - the sadness is less dense and less heavy.... and each time more peace and pure tenderness replaces the former feeling of total devastation.

The Life is helping us to heal the loss in small doses and gradually, with unexpected details that trigger memories ....

I can relate to your experience with the photo, that brought back the memories of your dear friend.
Huge hugs!!!