What is do i look like i know what a jpeg is?

"Do I look like I know what a JPEG is?" is a sarcastic phrase used to express disbelief or annoyance at being asked a question that seems ridiculously simple or obvious. It implies the questioner is assuming a lack of basic knowledge on the part of the person being asked.

The phrase plays on the familiarity of JPEGs (Joint Photographic Experts Group) – a common image file format. Almost everyone who uses a computer or smartphone has encountered JPEGs, making the question of whether someone knows what one is seem absurd in most contexts.

Therefore, the phrase isn't about JPEGs themselves, but rather a way to deflect a perceived condescending or insulting question. It's a rhetorical question; the answer is implicitly "no, I'm not going to answer your patronizing question because it's insulting."