I found out about the on-line photo offerings at the Denver Public Library through a geneology blog.
Not into geneology? Remember, photos are primary data.
The Denver Public Library has a searchable on-line database of over 120,000 of the images in their extensive collection. You can do a search by author, title or subject, but my favorites are the online image galleries arranged by subject. Within each gallery, you can view “all images” or a slide show.
Hint: If you choose slide show, but your cursor over the image to view the caption.
Now, if you’ll excuse me, I have some ol’ time photos to peruse. And these won’t even leave me sneezy.