Nope.

In order for a website to do a replacement as you mention, it would need to have facial recognition software installed... That aint happening... Images have varying file names and rarely do they clearly name who is in the picture... So even "if" there was a hack or mod that could do that the file names that it would need to have a list of to associate with a particular person are nearly endless.

If an image of someone bothers you... put a sticky over it while you read the post :-).