You can write an online book with your children and grandchildren. You can use the Google document below as a template. You can share the story by email. You and your grand children can write the captions for the photos together.
The Document below can be viewed and edited by everyone. If you decide to write your own book create a new Google document and paste the photos into your book. Add your own photos and invite only your family as editors. You can make the document public or private.
After you create your Gmail account click on the nine little boxes in the upper right hand corner and go to Docs or Google Drive, then Docs. Then create your online draft book. Give it a name, decide who can view it and who can edit it. In this case you, your children and grandchildren.
Create you own Google document and give it a name. You can then share it by email to those who you want to edit the document. You then decide whether you want to make it public for all to read or just limit it to your family. You can copy my photos and/or put your own photos and text in the document.
If you like to have a printed bound book there a number of affordable ways to print the book. Here is one.