I just noticed the problem today; not sure how long it has been going on.
Normally (historically) every image I embed has been clickable and enlarges to supersize. Now I'm seeing photos that not only fail to enlarge, but even appear smaller when one clicks on them.
The post below this one has a NASA image composed of photos of the moon. When I click on the photo, instead of enlarging to view details, I see this tiny image:
I don't know WTF is going on - whether the problem is with my computer or Blogspot or what. Bear with me. I'll try to sort this out (later).
Addendum: A comment by reader Kniffler seems to have steered me to the source of the problem, which seems to have been on my end (the browser opening images at the incorrect magnification). If so, it will not have affected your viewing.
As Gilda Radner's Emily Litella used to say on Laugh-In... "Never mind."