A few observations about trigger warnings that people don’t actually seem to understand:
If you post a graphic or disturbing picture on something other than tumblr (where Savior or something like it is not an option), it does NOT help to add a piece of text saying “trigger warning” above or below that picture. I am not even sure why one would bother. If your warning does not actually help anyone avoid the trigger you might as well not have one.
Also, I understand that it seems like a good idea to be thorough, and others may disagree, but I do think there is such a thing as an overly detailed trigger warning. If your trigger warning contains so much information that you are basically just summarizing the allegedly triggering text, such that people get stressed out just reading the trigger warning, you aren’t actually helping. The goal is to convey the minimum amount of information necessary to let the reader make an informed choice whether to proceed, without getting so detailed that you actually manage to trigger them yourself. In a situation where you’re tagging stuff so it can be tumblr saviored, you actually might want to go into more detail because you want to make sure you hit the right terms.
I don’t actually understand trigger warnings well enough to be able to generate them in any useful way. So I’m not entirely sure that I know enough to be able to evaluate this advice.
I think it sounds right, though.