Not only imgur.com, but I remember that I got an error using another hosting service, I don’t remember it specifically
Issues with images happened some times in the past but things were back to normal after a while.
Only months ago, serious issues from ingur.com and it lasted very long time. Later people changed to other sites, worked fine but later one or two sites got problems and some members reported it here.
I only mentioned about imgur.com because it caused biggest problems here.