It seems that half of the questions from new users have linked example images (better than no example at all) that we then edit to make the image inline.
Could SE automagically alter posts to turn .jpg and .png links into embedded images?
New users need at least 10 reputation in order to post images. They also need more than 10 rep to post more than 2 links.
This is mainly an anti spam measure and does not (usually) significantly affect the user. Considering 10 reputation can be achieved by one upvote on an answer or two question upvotes it is a trivial inconvenience.
It should probably be explicitly be stated on the privilege page but for what it's worth:
Why are restrictions placed on new users?
Because we allow participation from anonymous internet users, we must take some precautions to ensure that the rare malicious or spammy anonymous user doesn't ruin the experience for everyone else.
We're sorry that we have to sandbox new users, but the first few upvotes on your questions or answers will quickly elevate you out of it!
I believe that the settings are good in their current state. Yes, it's likely that someone with enough rep will eventually edit the post to embed the image for the user, and this make more work for someone. Still, I don't think it should be automated.
The problem with automation is that there's no review of the image before it is embedded if the system handles it. I haven't seen enough to know, but I'm guessing that spammers often try to use images in their posts and the post "seems" ok and isn't flagged as span. Yet once someone edits to embed the image, and sees what it is, the spam flag is invoked. Once (if) automated, those spam images would be posted for everyone to see, and remain their until enough spam flags were raised to get it removed.