Photos aren't an issue for me as I don't have many. Family photos in general landed with my sister, I have no idea what she plans to do them with in the end. The few photos I do have are mainly in a dresser drawer in various envelopes. If you have several photos of the same event or people, it's a matter of deciding which really seem best, hold those, either scrap the others or send them to other people (anyone who is in the photos). I have personally taken so few photos myself that this is not an issue in on in on in my situation. my camera still has film in it (likely not useful) from 2002.
Personal items are a little trickier as things can relate to a memory which we don't want to ever be broken from. Another member here had a troublesome time with a spoon, it connected to fond memories; however, due to it's design (a design on it) there was an edge of uncomfortable. In the end they closed by stating: " have very few happy memories of my mother. The spoon is connected to one of them. I'll hang onto it. My heirs will have to decide what to do with it."
There isn't a great amount of personal related to family stuff in my holdings, I have a cast iron casserole and an old manual egg beater from my grandmother, neither of which I ever use but I can't part with them. I have my grandfather's dressing bureau from back when he was still stateside and married to my grandmother; but, it is in constant use so it's less of an oddity.
Stranger items are a hurricane lamp, with a depiction of The Last Supper on it. My mother gave it to me and I am unable to part with it although it is not something I use or really want. Considering my thorny relationship with my mother, I can't explain why I've held on to it. Weird.
I don't usually attach to personal possessions, most I can dispose of with little to no thought or care. Some, bring a few moments (or days) of sadness when I let the item go, or am forced to dispose of it (because it is in such bad shape), nothing seems to draw me into a space of feeling bad for a long time.
My hardest disposals are books. I never like giving up a book.
My bigger concern is the many items I've written over time. Letters, stories, poems, even a book and a few partial books (I seem to lack the ability to finish things). For a long time I had every last piece of them, from initial starting idea, to first draft to second and on until the final product. Slowly I began tossing out the middle parts, leaving me with the start and the finish (when there was a finish).
Papers and writings are an interesting thing. They can offer an insight into the person, your son could get a different take on you, maybe appreciate that you felt a reason to hold on to them or he may wish to hold on to them as his way of having a connect with you when you are gone. I still have papers from both grandparents which I treasure and read at times. They have no direct meaning to me, the content is not about me, it's most all from before I existed. It does offer me a calming though when I read them or even put hands my hands on them.
When I die, my stuff will most likely end up in a landfill. My brother never involves in these things and my sister is like our mother and just throws stuff out without giving it a lot of thought or consideration...if it belonged to someone else. (although her own home has her clothes from when she was 12 years old and all manner of other trinkets from her childhood). She may do a quick browse, or send my niece or nephew to tend to it, I can see them carrying a laptop computer around hooked up to Skype or some other thing, and my sister will declare "oooh that looks nice, pack it up." or "what books are on the shelves" or "does he have any good condition sweaters, sweatshirts, shirts, jackets?" - she is good with a sewing machine and alterations; and even if she weren't she likes loose fitting garments. We are both slim, and I'm only 3 inches taller than her, so she'd manage. When we lived in the same city she often took my shirts and never bothered telling me and twice took jackets and altered down to her own arm length.
Maybe she'll want my refrigerator magnets.
At any rate, these days I'm in an apartment, and often NYC apartment contents collide with dumpsters when a tenant dies and the local street dwellers sift through grabbing what they can get a few dollars for. Other items are sometimes grabbed by locals looking to refurnish or get a new set of dishes. Hopefully somebody will check that suitcase with the glassware. (this may be a genetic thing, my grandmother had a suitcase filled with dinner plates).
I've heared at times that anything which hasn't been used for a length of time should be tossed...that never made a lot of sense to me, especially with the 6 month version, which would mean getting rid of any holiday related things.
Go slow and easy, dispose first of things which are of no interest (including in photos and papers), see how that feels, then move on to other items and decide according to how comfortable y0u are or aren't with getting rid of things. If you feel you can't, then explain it to your son and let him know he is in no way obliged to keep anything. Advise him on the joy of having a tag sale as a way to get rid of things, maybe get a friend or 2 or even 3 to help assist him in that.
I am sincerely hoping others will give advice on this as mine seems to be written by a crazy person. Bottom line, stop worrying, it will all work out the way it should in the final picture.