This subject is debated quite often. I know that studies have shown that showing horrific pictures to people actually causes denial rather than promotes safe behaviour, but people still think they will work. The same debate has recently come up in the LinkedIn EHSQ Elite Group. Patrick Hudson provided some great information that is shown below.
The use of vivid, scary or bloody pictures is often believed to be a guaranteed way to make people behave safely. The evidence is clear that this is wrong, yet the police like to use them for road traffic and industry likes to use them for getting workers to toe the line. What does work is the possibility, as used in the best horror movies, where the threat is always implied, the blood in the next frame and the engagement of the viewer is not turned off by the sight of blood and mangled limbs. The turn-off factor means that people move to deny that it will happen to them, it only happens to others, and this is, if you think about it, likely to produce exactly the opposite behaviour in your workforce to the one desired (it won't happen to me so I will carry on as I always do). The people who propagate the use of scary material are already won over, or are in a senior position so they aren't personally confronted with the problems.
What you CAN do is involve the workforce in learning to spot and recognise hazards and get them to convince themselves (not by preaching from a superior pulpit) that they are worth avoiding. This is part of the Working Safely model in one of the Hearts and Minds tools, based upon trying to understand what it takes to work safely as opposed to asking why people work dangerously. The empirical evidence then shows that many accidents are the result of either failing to perceive the hazard in the first place or failing to regard it as sufficiently dangerous to do something about, in a world with many hazards that require people to prioritise. If after 35 years you haven't been hurt, a 5 minute lecture by a consultant is unlikely to convince an experienced worker that 5 minutes by someone from outside are more valid than their 35 years on the job experience (even if statistically their experience is too little on an individual basis).
By the way this approach works in South East Asian cultures. In my experience no one is so fatalistic that they, personally, are happy to die to get the job done for someone else. Peoples' behaviour in the face of hazards, seen as their response to risks, are complicated (as high-paid bankers have shown us) and sometimes I get frustrated that authorities feel that they have an adequate knowledge of these factors in people, while they would never dare have the same presumptions about financial or technical issues. If they know about Prospect Theory and why Daniel Kahneman won the Nobel prize for his work with Amos Tversky in this area then I might be prepared to give them some more listening time. The use of shock tactics to force people into passive compliance is an indicator that the proposers are amateurs who have come up with a solution that, in the words of H.L.Mencken, are "simple, neat and wrong".