I am encouraged by the responses here. I remember when I received announcements from 2 nephews, it made me smile, remembering them as they grew up, and I still have the announcements and photos.
We won't be having a party for DD's graduation. We only have 5 graduation tickets, and both my sister and brother have asked about attending. They are the only relatives within driving distance, so they'll drive up for the weekend. We have a ticket for each of them, DH, DD's boyfriend, and myself. My sister will bring her 2 daughters (14 and 17) with her for the weekend, but unless we can score a few more tickets, they won't attend the ceremony. We'll probably have a celebratory lunch/dinner here at home, as we live in a small area and there are several graduations that weekend (as well as being Mother's Day weekend); I know all the restaurants will be PACKED!
DD didn't have formal graduation photos done, although they were available. The photo I will include is her head shot from this year's sorority composite. They have them taken every year but I never order. However, this year's pictures were beautiful, and I couldn't help myself! They are the only pictures she's had taken since senior year of high school, and I can see a change in her face over those 4 years.
Facebook isn't an answer, as none of the grandparents and most of the aunts/uncles don't use social media. While I am sure that Grandma knows about graduation, she has 22 grandchildren, so it's understandable when aunts and uncles lose track of where in the "growing up process" any one grandkid might be, especially when we only see them once a year. However, just because we are separated by distance doesn't mean we are separated in our hearts! I will send announcements to Grandma, the 2 grandfathers, and the aunts/uncles. I know I am happy to have my nephews' announcements and will assume they'll be glad to have DD's! Thanks for your opinions!