Does the Playstation Vita have HD graphics?

Answer 1

"It does... its only 540p. Its determined by the screen resolution and PS vita's screen res (960x544) qualifies as hd"

Actually that isn't true HD.

Anything below 720p is considered either Standard Definition or Enhanced definition. The PS Vita is 540p and thus qualifies as an enhanced definition system. But its not a true HD device.

And while the resolution may seem rather low, you have to take into consideration that the screen on the console is only 5 inches, which is big but still small enough to make the screen appear crisp.