I'm friends with Taylor Swift, and I am tired of people asking me questions about our friendship. When I post a picture of us on Instagram, I'm posting a picture of me and my friend.

This quote means that the speaker is annoyed that people are constantly asking them questions about their friendship with Taylor Swift when they post a picture of them together. They feel that they should not be continually interrogated and that they are just sharing a photo of themselves together like friends do. The speaker believes that they are entitled to post a picture of their friendship with Taylor Swift without needing to explain or justify it.