My mother had shunned me for several years after I left her cult but after I had kids, she suddenly got all friendly and wanted to start up contact again, especially with her two grandkids. We told her we didn't want her talking about her religion to the kids. She went behind our backs when babysitting them one day, showing them such illustrations. My son was about 6 and it didn't seem to bother him. My daughter was about 4 and it affected her badly, frightening her to the point where she fretted about us dying in such a horrific manner, breaking into tears at times. She also started wetting her bed and having nightmares, it was so stressful for her.
So you can't say it's no big deal, that it's just like the comics or movies. All kids are different, some can't process such heavy info, some are more sensitive than others. My daughter is such a sensitive little soul, always has been, and is today at age 28. JWs use them to brainwash kids and frighten them into obeying the cult. It's sick.