For content that is covered by intellectual property rights, like photos and videos (IP content), you specifically give us the following permission, subject to your privacy and application settings: you grant us a non-exclusive, transferable, sub-licensable, royalty-free, worldwide license to use any IP content that you post on or in connection with Facebook (IP License). This IP License ends when you delete your IP content or your account unless your content has been shared with others, and they have not deleted it.So what this says is that Facebook can use any of the Bloom County strips that Breathed posts for whatever they want to do with them. Theoretically, this could include advertisements or the publication of a Bloom County book. I don't think the resolution Breathed is posting the images at would transfer well onto the printed page, but that's not the point here. The point is that Breathed, by posting the images to Facebook, is giving them a license to use it how they see fit.
That's true of all the images we all post there, of course, but I'm fairly confident that a sweaty selfie of me halfway through a six-mile run isn't going to be of interest to anyone outside of a very select group. Most of the images we post are context-specific -- that is, you have to know who the person is and why they're posting what they're posting for it to be of any real use.
But a comic strip like Bloom County is largely has all the context that's needed in the strip itself. It's a self-contained story that makes sense regardless if you know who drew it or why.
Breathed doesn't seem overly concerned about generating money out of his new Bloom County work at the moment, but I suppose the question is whether he's okay with Facebook doing that even if he doesn't. And in an era where it's dirt cheap and relatively easy to set up your own site where there's none of the legal concerns I'm bringing up here, it's curious to me why Breathed would choose to host his new strip on Facebook.