400 error for profile image — every other time, every time [duplicate]

Answer 1

For me it's a similar problem, I got round it by displaying less images then I was doing (I was trying to request 20+ images at once), now I'm only requesting say 5. Seemed to fix my problem.

Answer 2

You are accessing the image as you are supposed to. Log a bug with Facebook (not that you will likely get a response) for any issues.