"incorrect filename" is a popular way to derail a thread. It consists of a person posting an image, and putting an incorrect filename next to it.
According to the encyclopedis dramatica, the most popular image/ filename to use is a picture of link with his hand clasped over his mouth, and the filename reading: laughing elf man. Presumably, the idea behind this is that other people on the thread will begin talking about the ignorance of the poster, as opposed to the actual subject of the thread. The meme first appeared on 4chan earlier this year. It was first posted by a member of anonymous.
Below is the first recorded instance of this meme

It was tagged as <<bald yosestame sam.

below is another example of this meme in action: