It stands for: This thread is usless without pics.
This term is used in a thread on a message board when someone posts a news article or webpage where a picture would be beneficial in understanding what is going on in the news story.
WIthout the picture the thread can be termed 'useless'
Article Headline: Britney Spears appears topless on the beach in Rome.
Article: contains drizzle about her trip to Rome and her marriage to Kevin what's his face.