It was yesterday that this error occurred. First time seeing this happen. Prior to this error, the project failed to load and I was told that the Scratch Team has been notified. After that, the images failed to load.
This error continuously happened even after several reloads, so I gave up later yesterday. Came back today and the same error popped up…
Project link : https://scratch.mit.edu/projects/97513212/
Pic:


My browser / operating system: Windows 7, Chrome 56.0.2924.87, Flash 24.0 (release 0)

Getting the same Error on one of my projects, I tried deleting the sprites with errors to see if it would fix it but it just created more sprite errors.
Project: https://scratch.mit.edu/projects/141164138/

Try uploading the image as an sprite.

Seems to be working now so might of just been a hiccup on server or something.
But it did swap some costumes with ones from completely different sprites on it's own so had to fix that.

Well, mine still happens at this particular machine. Works fine on everything else.

if this shows up, , that means it does not exist,