Symantec contributor Fred Gutierrez shows clearly in this blog post why it can be deadly to click on a .JPG file:
"Cybercriminals have continuously evolved their methods throughout the years to avoid detection and arousing the suspicion of the users they are targeting. In the case of targeted attacks, the lure is a critical piece of the puzzle, as cybercriminals need to be sure they can get the attention of their target so they can convince them to run malicious PDFs or DOC files." Here is the full article
"Cybercriminals have continuously evolved their methods throughout the years to avoid detection and arousing the suspicion of the users they are targeting. In the case of targeted attacks, the lure is a critical piece of the puzzle, as cybercriminals need to be sure they can get the attention of their target so they can convince them to run malicious PDFs or DOC files." Here is the full article