Okay, to take a full stab at this, here is a more detailed reasoning. To provide some context, I just finished reading Jeff Atwood's blog entry on Informavores. The large carry-away is the note on information scent:
So if you've ever wondered why users behave like animals online, now you know. There's real science behind it in information foraging. Instead of hunting for food, users hunt for information, ruthlessly, and without compunction. In practice, what this means is that users pursue "information scent". Users will click the back button nearly instantly when they don't catch a whiff of the right information from the current page.
The purpose of the Stack Exchange network is to answer questions that people need answered. It isn't to stroke a curious spot; it isn't to idly wonder what-if. Our target audience is someone asking the internet a question. Our competition is everyone else attempting to answer the same question.
In my opinion, people asking skeptics-style questions are not interested in pretty pictures. They actually want the exact opposite. Graphical information that isn't actually relevant to the question is lacking information scent. We have very little time before our audience makes a judgement call and walks away.
This is why editing questions is important. Questions need to confirm, as quickly as possible, that the topic on hand is relevant to the question our visitors are carrying with them. If we match up, we get a chance to charm them with our answers. Not charming pictures; charming information. If the pretty pictures help generate a positive information scent, let them stay. If they are chaff, they should be edited out.
This leaves a large discussion about what images provide this information scent and which do not. A few of the answers here give some credence to the value of images:
As I said in another discussion point, I try to use images in my answers, because it should help people remember the answer. A neurological study supports this.
To enhance an answer by
- Providing additional information
- Clarifying written information
- Providing an alternate view of the same information
- Attracting attention to a particular point or issue within the post
I think these are helpful in determining which images are useful. I explicitly do not think "Because they are fun" is a valid point. "Fun" is for people who browse the site idly looking for interesting things. Those people are important but they are not our target audience. Our targets are people who need answers and they are impatient and need them as quickly as possible. "Fun" does not help information scent. A picture that provides no use other than "fun" is wasted processing time for our visitors.
That isn't to say "fun" is bad; the point is that "fun" should be secondary. Once we have them hooked we can bring out the fun. Even Jeff's blog has a picture of an animal doing its thing. But Jeff's blog is a blog. The "useful content" to "fun" ratio is different for a blog than it is for a Q&A site. The "useful content" to "fun" ratio of a question with two paragraphs and a picture is crap.
That being said, naturally different editors and authors will have their own style. But Skeptics.SE isn't here for you to test your blogging/writing skills. It is here to answer questions and answer them more accurately than anywhere else on the internet. "Fun" is important but it isn't so important that we should sacrifice the practicality of the SE format.
And this isn't to say that a site full of useful (and efficient) information is unfun. It is the exact opposite. A visitor popping in to find the answer to a question wants... the answer to the question. The answer to the question is "fun". Going into a book store for a book and getting bombarded with "fun" isn't fun. You just want the damn book.
The idea that removing unneeded images will reduce the "funness" of the site is losing focus on what makes SE valuable to the internet. We are not daycare for idle minds who also happen to find Skeptics questions interesting. We are here to answer questions and provide information. The best way to convince people we know what we are talking about is to increase our information scent. "Fun" pictures don't do that. Accurate and accessible information does that.