Well, @Carriolan. I did some more digging. I’m not sure why turning your attachment folder off doesn’t work. So, I turned mine on and fiddled with those queries. I found that for me, the following query excludes JPG’s and PNG’s:
file:-".jpg" and -".png"
Hopefully, it’ll work for you. Otherwise, we’ll keep thinking.
Also, if that doesn’t work (and this is kind of obvious, just checking the boxes off) but you did actually SET the attachment folder by right clicking it and clicking Set as Attachment Folder, then confirming it in settings, under files and links, that the folder path is correctly set, right?