I hesitate to vote 'yes'...
Reason being: many (if not all) screenshots I personaly have made in the past can be categorised in two sections: screenshots which can be used again, and screenshots which can't be used again.
The first one (sshots which can be used again), can quite often be found by looking in some other posts and can easly be reused (by simply linking to them). Making a proper help post would already include such a screenshots.
And when you come across the same question somewhere else, it would be better to link to that older post/thread anyways instead of starting another thread with the exact same thing (resulting in the exact same followup questions, same comments maybe etc. etc. Which means you as a helper need to put more time in it than needed, the user needs to wait for repsonses, and the forum would contain 'duplicate' threads with information scattered around)
The second one (sshots which can't be used again) are actually very common too. This is because many stuff is specific for a particular person for a very specific question. Such screenshots can't be used for other people or it will make things more confusing instead of more clear.
Another reason why I wont vote yes, is because, imho, if you make a databse, then such a database should be made together with help posts, thus with text, explainations. Making such a proper help-database would already include screenshots (eg: see stuff on the official Messenger Plus! Live pages).
All in all, the most common problems you come across on these forums (and even not-so-common problems) have already be handled in one way or the other, and most of the time that included a screenshot (for those questions which aren't user-specific).
The only thing you need to do as a helper is searching for those posts/threads and link to them (instead of being lazy, if I may be so bold to say it, and without pointing to anyone). And if there isn't such a older post/thread then make your screenshot and use it to answer the question.
Yet another reason is the same as what I've said
here: info fragmentation. This idea of a sshot db is great, but is yet again one of the many many many things which is started up and then forgotten or not used while there are already sites/databases which could perfectly do this (refering to
http://msupport.net) if they are only maintained and updated properly by people (and with 'people' I don't only mean the creators of such sites, but us, the helpers, mostly).
So, I feel that making a new database with screenshots would be like seriously re-inventing the wheel since a lot of the screenshots which would end up in this database actually already exist....
So, I wont vote 'yes'...
(Though, I wont vote 'no' either, unless I really really must choose, then I would reluctantly choose 'no')