Please give her a "Trip Down Memory Lane."
My sweet mother (88y/o) died this past Nov., the week of Thanksgiving. We have been cleaning out her 4 bedroom house and have found boxes of old photos, news paper clippings, her H.S. yearbook, the speech she wrote to read at her graduation, (she was Valedictorian) family bibles dating back in the 1800's, a laundry basket of full of jewelery, etc. How is wish I had gone through this stuff with her.
If she has old stuff that still needs to be gone through, go through it with her. Ask questions, let her talk about each piece, the story behind the photos, and just listen as she shares her memories.
If they've already gone through most of her belongs, make a scrap book for her. Gather old photos, cards, letters, newspaper clippings, etc., and present them to her in a scrapbook.
Another idea... When we are invited to SURPRISE parties, I buy all the supplies to make a scrapbook of that event. I include the memory album, card stock, related embellishments & stickers, etc. I also buy 2 or 3 disposable cameras and take a bunch of pictures while there, then toss those in the gift bag, too. Those receiving this as a gift have always been thrilled and greatly appreciative. (Hey... if they were truly surprised, they didn't have a camera with them when they arrived at the party!)
*Since your Aunt is 90, you should probably take the pictures on your own camera, get then developed, and then go over and help put the album together with her. Win - win... because you are spending time with her.