It seems that malicious individuals have discovered a new way to ruin your day. Serial leakster Ice universe has discovered a specific wallpaper that crashes your phone and sends it into a reboot loop.
His followers have vouched for the authenticity of the claim after trying it out themselves and encountering the same issue.
All hope is not lost however, as you might be able to solve the issue if you manage to enter safe mode and switch out the wallpaper; if you don't, then the only thing that will help is to factory reset your phone.
So, if you're not particularly fond of potentially losing your data, do not set this as your wallpaper if you come across this wallpaper. It is not known whether there are other wallpapers circulating that will trigger the same issue, but as Ice universe has tweeted his suspicions that it is related to colour gamut, it's best to stay safe and be wary when downloading new wallpapers.
Samsung has apparently been alerted about this issue, and will be rolling out a firmware update to address it. Until then, perhaps it's better to set your pet / partner / own face as your wallpaper for now.