I think a photo book would be great. I recently made one online through BigW of our overseas trip we did back in 2004, we took PIL with us & we spent 11 weeks travelling through Europe, UK, Hong Kong & Japan so we had plenty of photos. The normal photo albums we had were heavy & looked quite unorganised, the new photo books look fantastic!
I got to pick it up from my local store too so didnt have to pay for or wait for postage
It does take a while to do but I think its really worth it! Especially if its for someones 100 years!!

Well done to her, how fantastic getting to 100!!!