It means that the image is likely to get the working folk fired if it's seen by a boss.
'Link it' means to replace the image with a link to it, eg:
Sexual Frustration (NSFW).
The NSFW means 'Not Safe For Work'.
( ,
Fri 16 Mar 2007, 15:37,
archived)
Sexual Frustration (NSFW).
The NSFW means 'Not Safe For Work'.