I have used "Pioneer Photo Albums Bund Top Loading Page Protectors with White Inserts, 12 by 12-Inch, 5-Pack" for photos and memory books for many years.  The white paper insert is sturdy; it is easy to attach either photo corners or self-adhesive photo squares that will then hold your precious memories securely.  If you have not space between photos, one-side of one page will hold six 4" X 6" photographs.  The covering is similar to an acetate film, but it is not acetate and is safe for photographs.  The three-hole border is reinforced and the holes have a small slit that allows you to use these pages in albums other than Pioneer products.