I would like to open something of a can of worms
I mentioned this already some time ago, and a couple of other did as well.
Would you consider changing the forum software completely? SMF shows it's age.
Several communities i'm a member on are using Xenforo (
www.xenforo.com), and i came to like it a lot. It is modern, with a seamlessly scaling UI depending on your device, and at the same time keeps the look and feel of a forum. Unlike for example Discourse
The WYSIWYG Editor works well (and can be switched to a non-WYSIWYG Editor), and you can just drop an image into any post inline, or attach them as well. A well working notification system. A great quoting system, giving the opportunity to easily avoid fullquotes.
Its paid software, but it is not expensive.
Though of course i have no idea how much effort a migration would be. They say they have a SMF 2.0 importer, but i have no idea how well it works
What about a new software entirely? https://www.vbulletin.com/ comes to mind...
But only as a last resort. Lost the highly valued "Tonmeisterforum" forever because of such a move. Conversion didn't work and backups also didn't work. Was an extremely valuable resource, I am missing every day.
Ooof, that hurts. But that the forum was lost that way shows incredibly poor planning by the webmaster of that site. Test your backups, people!