Speaking of Cindy Sherman, the online Cindy Sherman gallery at MoMA's website is fantastic. In case you don't already know, Cindy is probably the world's most famous female photographer, and mostly known for her self-portraits. If you want to see a large collection of her work, start here:
And then click on the orange link that says "View exhibition site" near the top left, after reading the intro, if you want to. Once in the exhibition site, you can visit a series of "galleries", but I find the chronological view to be more interesting, especially since it helps to understand where she's coming from if you see her work from the '70s where she re-creates film stills from non-existent movies. I find many of these photographs to be stunningly good.
To view the works chronologically, use the menu in the bottom left of the screen and select "Works Chronologically". Double click on one of the photos to make it big, and then you can use your right and left arrow keys to scroll forward and backward in time, seeing one large photo at time. Maximize your browser, as the photos will expand to fill it.
Beware that after you get out of the 70s, some of the works are rather gruesome, and NSFW. Especially works in her "Centerfold" series. If you don't like gruesome, then stop when you hit the 80s. Though in that case, you might like to backtrack from the present, as she's been continuing her work to this day.