Despite the person’s photo would show the default Facebook image, what has to cut your attention is the name.
See: How To See Who You Blocked On Facebook
If such a friend’s name appears in black bold color, and at the same time the name cannot be highlighted as to be clicked on in order to visit the person’s Facebook profile, then this suggests the person might have blocked you on Facebook.
This is one tip which helps you answer such questions
METHOD 2: Another tip on how do I know if someone blocked me on Facebook is to try reporting a conversation with a friend as spam.
Simply re-open the message page and the conversation you have had with the person. And then from the menu at the top right of the pop-up screen, tap on “Actions” and then select “Report spam or abuse”.
A new window will open at this point, then select “Report one or more participants in the conversation for harassment or threats, or have a compromised account”. Then tap “OK”.
Another window will open, but then if the window opens and reads “Operation prohibited” right to the user’s name, then this suggests the Facebook friend or user has blocked you on Facebook.
METHOD 3: This third tip seems to be the easiest method or approach. All you need do is to ask a mutual friend to access the person’s (the Facebook friend in question) Facebook profile. I mean the person you think has blocked you.
If that mutual friend can access the person’s Facebook profile whereas you cannot access the same person’s Facebook profile, it simply means the person actually has blocked you.
Bear in mind that this is all on Who Blocked Me On Facebook on Facebook social media. If you have followed this step, then you can certainly determine whether a Facebook friend has just blocked you.
But then, if you have been blocked by a friend on Facebook, do not stress yourself. This is because the person might have a reason for blocking you.
It is advised that you reach the Facebook friend by another means you can, to at least find out why, but if you couldn’t, they don’t really worry, after all, is Facebook; a social media platform and not a real life situation!