Prior to answering this question about Fallout 4 screenshots, I searched the site for a more general "Steam game screenshot location" question but couldn't find one. Would it be appropriate to edit the title and tags of the question to make it apply to all steam games in general? Would it be better to ask and answers a more general question and mark the FO4 question as a dupe?
I agree with StrixVaria - don't edit existing questions to make them more general. If you feel that having a "Where can I find my Steam screenshots?" question is useful then go ahead and ask+answer it. Let the community judge whether it is a duplicate, or other questions are a duplicate.
Regardless, I feel that this question is probably the one you are looking for:
The title of the question could probably do with a little tidy up to make it easier to find. Other than that I think that this has enough in there to help people find the screenshots for most Steam games.
Don't edit other questions to ask questions you want to know the answer to. Just ask your question on the site and we'll figure out any duplicate issues as they come up.
Having duplicates on the site isn't bad, and having your question closed as a duplicate isn't a bad thing and doesn't reflect poorly on you. If you made a good faith effort to search for the answer to your question, and couldn't find it, then your duplicate question may help someone in the same boat as you down the line find the right question.
As an answerer, your responsibility is only to answer the question as asked. Our site is not intended to nor should it become an encyclopedia of gaming knowledge. It's a Question and Answer site. In 99% of cases, people should ask questions as they run into practical issues during the course of playing games, and people should answer the questions asked to help people who have run into these difficulties.