I remembered to grab my phone to snap 2 pictures of mom and her girls while everyone sang happy birthday, but I now wish I had taken more. After the party, the mother emailed all of us guests asking for any photos taken at the party, as she hadn't taken as many as she had planned.
I still cherish a photo that a friend took at our son's birthday party last year. Somehow she managed to get a good photo of the 4 of us, something that was especially challenging when our daughter was only a baby.
For our son's second birthday, we were lucky enough to have a friend offer to take photos and videos for us during the party. I remember so much from our son's second birthday party because we have many photos of our guests, the games, the food, etc.
When we attend our next birthday celebration I'll be sure to snap at least a handful of photos, hopefully more. It can be challenging to host an event while taking photos to remember it. But, a handful of photos won't take much effort for me, as a guest, and it could make a big difference to the family celebrating.