If the grandparents enjoy getting physical mail and like hard copy photos to have around the house, then https://nanagram.co is a good option[1] You just text in your photos and they printed and shipped once a month. We use it for my mom to send baby photos and she loves it. [1] Full disclosure: my older brother built this service, but I don’t have an affiliation other than being a proud brother and happy customer. - Source: Hacker News / about 1 year ago

Nanagram- hard copies of photos sent on a monthly basis. Great for the scrapbooker family member. Source: about 1 year ago

I'm not affiliated, but I have been using Nanagram for the last couple of years to send prints to my Mom. Source: over 2 years ago

That is adorable. You know what she'd love? NanaGram. Send her back 3 photos of you for free on our home page. Source: over 2 years ago

4. Grandparent gets envelope of printed photos just like the ones filling their old albums on the shelves It really is that easy. It’s affordable. And the founder is very responsive to any support inquiries. It was a service I always wanted to build myself but never had the time. I’m very grateful for it. [0] - https://nanagram.co/. - Source: Hacker News / about 3 years ago

You are responsible for tracking your package, communicating with USPS, and telling us ASAP if there is a problem. Enter your tracking number at www.usps.com . After the package enters the U.S., register for Informed Delivery updates so that you don't miss your delivery: https://informeddelivery.usps.com/box/pages/intro/start.action. Source: about 1 year ago

Sign up for Informed Delivery and at least you'll know if you're supposed to get anything. Source: over 1 year ago

If you want to see what's coming in your mail, this is a free service! I get an email every day with pictures of what's coming,and package tracking info. https://informeddelivery.usps.com/box/pages/intro/start.action. Source: over 1 year ago

You might want to sign up for Informed Delivery from the USPS. It's free. They basically send you a B&W photo from the sorter machine of mail that's coming to your address. It's a good way to know if your mail has gone missing. I use it mostly because I don't get much junk mail and it saves me time from having to walk to the mail boxes at my apartment every night. Source: over 1 year ago

Sign up for Informed Delivery if you want to keep track of USPS packages. UPS and FedEx also have their own portals that let you keep track of incoming packages. Source: over 1 year ago