I think they made the right call on this example -- the whole point of SO is to get specific answers to specific questions. This question is vague and without the context that a reasonable person would need to give a specific answer.
There are plenty of examples of good questions being closed because they are perceived as generating too much discussion (esp. on the "programmers" se site). IMO, you've given us an example of SO moderation working.
Please elaborate. If I want to know the pros/cons of storing images in a database, vs. (say) storing only the links to images in the database, what more specific question should I look for? How is that question too general or vague? Apparently at least 400 people thought it was reasonable, than thought it was unreasonable. 50+ people thought it was reasonable enough to respond to.
That's like asking "What is the best way to drink milk"?
In the case of milk, circumstances matter. Is the person drinking the milk an infant? Lactose intolerant? Travelling? Going on a 1-week camping expedition? On a diet? Diebetic?
The details are key to the question. If you answered the question "In a glass with chocolate chip cookies on the side", the parent of an infant following that advice would have a baby vomiting everywhere because they cannot digest milk protein.
The database question is similar. Are you storing favicons or 10MB RAW files? Is the database an archive with low traffic or the next Flickr? What database platform are you using? What resources are available to the questioner?
That seems to be the consensus here. I disagree with it. A clear invitation to discussion would be "What would you do?" not "What are the pros/cons?". There are plenty of valuable programming questions I can think of that can possibly devolve to some level of discussion. Banning all such questions greatly degrades the site and makes me not want to ask any questions there. If I ask "What is the function parameter in this particular language that I use to do this particular thing?" there could still be differing opinions and so the question could be locked.
There are plenty of examples of good questions being closed because they are perceived as generating too much discussion (esp. on the "programmers" se site). IMO, you've given us an example of SO moderation working.