You could print out your pictures, and do a mashup, and then write about what was going on in the pics, the reason you took it, how it makes you feel? Or just write what you want and then find a pic you have taken to paste/glue onto the page, inspiration??
(as you might be able to tell, I am big on incorporating what we love to do with something that is hard to do)
It's not right for people to try and invalidate how you feel about your grandfather, but it's something special you had, and other people's words cannot take that from you x