Posting photos on social media..what about copyrights?

[bcnu]

Copyright enforcement is somewhat like walking through the woods without knowing whose property it is: some property owners won't care, as long as you're not doing any damage, others will come after you and order you not to do it again, but they won't sue you unless you've done damage.

Unfortunately, you could violate a "registered copyright" in the USA and be at risk of being sued for up to $150,000 for each image you upload illegally (which is an unauthorized reproduction, public display, public performance, and/or distribution, all of which violate copyright).

Like Andy says, you only have permission to view things on the web, not to upload them anywhere else, although there are minor exceptions for things like use in a non-profit school classroom.