hey I get the same thing all the time.

1 post failed to post. You were rich in my eyes: Image upload failed and Link to Reddit is disabled: Image upload failed on lemmy.world (image/jpeg, 0.13 MB). /pictrs/image returned HTTP 500 (request a26dc4d60f01bacc-IAD): {“files”:null,“msg”:“No such file or directory (os error 2)”}

I think you are running out of space on tmp filesystem