It appears that photo images in Known standalone installs are disappearing somewhere in the hundreds of photos ranges. Two examples have been found by paging back through the photo content view.

Example 1: @jeremycherfas’s photo stream starting at offset 550 shows photo images, however if you click "Older", you will see the photo posts, but no images, instead only alt text being rendered.

E.g. this photo post and older ones are missing their images.

Example 2: @benwerd’s own site, werd.io, shows photos backwards through offset=420, however if you click "Older" there, you will see at offset=440 (or perhaps the next one) that one or more photo posts are missing their images, and are falling back to rendering only their alt text.

E.g. this photo post is missing its image.