I decided that it would be great to have some more relevant stickers for my Needlework Book of Days - so I decided to make my own.
I took some photographs from my blog, Shortbread & Ginger, reduced them in size and added them to a A4 page in Publisher (you could use Word). I made some of them into shapes like hearts and circles and added these too. I choose photographs of my knitting, cross stitch, vintage china, flowers - all sorts of things!
I got some special sticker paper which can be used with inkjet printers and printed the page I had made. (My first page didn't fully load because I forgot to change paper type to special on the printer! But I got enough to start with.) I sat and cut them out while watching tv - didn't take long and actually quite satisfying!
Then I added a couple to my Book of Days! Perfect. You could do this with family photographs and all sorts of pictures to add to any journal, diary, planner or calendar. Using sticker paper (I got mine from Amazon) saves you having to find glue and means that you can have lots saved for adding when required. I also made a "hidden" paperclip with a cute little bird picture.
Hope this gives you some ideas.