Hello @user7791609 ,
This isn't an option, and I'll be honest when I say that I've never seen such a function in emails. When such images are included in emails, the options I've personally seen include:
- providing an obvious content warning at the top of the email
- including a generic filler image with text in that says something to the effect of "some may find the contents of this image unpleasant, click here to view the image / album," then link the image to the actual image/album.
- an advisory bit of text before linking to a fuller album / article with the potentially unpleasant graphics.
Beyond that, there isn't really a way to hide this in emails, the same way that social platforms do, nor a way to emulate the "hidden" / disappearing effect for text messages.