I think limiting to subscribers would probably limit the utility of being able to post photos for some folks.
For example, it would be really useful if people asking antenna questions could take some pictures of their installations or backyards or whatever... not all those people would be subscribers.
But it's certainly true that images provide a very serious moderation challenge. If it's not too technically difficult, some kind of decentralized moderation would be useful.
There could be a "flag this image" sort of thing that first off, immediately makes the image disappear if any user finds it objectionable. Then it passes it on to the mods for the final judgement call. Users who get flagged too often (or even once?) and have that upheld by the administrators could be banned from posting images, and users who flag not-actually-problem images could have their flagging privileges taken away. That way "almost everyone" could post images and "almost everyone" could make them vanish in an instant to prevent spam, pornography, stupidity, etc in a way that was very fast and generally didn't involve any obvious moderation action.
It would be massively helpful in some threads to post drawings or whatever. I do that routinely already but I have my own hosting for them. There are a lot of situations in which the saying about "a thousand words" is nearly literally true.
I wonder only showing a link to an image would help? The "mischief impact" and therefore desirability of mischief of an image that isn't actually displayed in-thread is probably quite a bit less than if it's just sitting there. Once you've seen it you can't "un-see" it

.
I don't know what purposes Tisha has in mind, but I think that for the purposes of forum discussions, a link to an image is probably nearly as useful as in-line images (especially for those using tabbed browsers). However, even to post links now, those without their own website or third party photo hosting account have to sign up first. And as sites disappear or delete images, the loss of useful and illustrative image links from old eHam threads would be detrimental to future readers.
73
Dan