bkeblen wrote: … This does work, but it is lower quality.
By golly, you're right! Most pictures I've tried end up being less than 1200 pixels across.
Drag & Drop, and copy & paste are not directly supported, and what they copy (original/edited, full sized/preview, etc) isn't specified. Just what's copied seems to change from OS to OS. Drag & Drop I know to check with each update, but I'm surprised by copy & paste. Since Photos has all sorts of versions of a picture available, copying might require a dialog page like Export has to make total sense.
The failure of the Photos picker in browsers has been a problem since Ventura, I think. No one knows why. So when I've needed to insert a picture, I've exported the image to a Finder folder, and inserted from there, like I referred to before. Export gives you much more control over what's inserted.
Another way to go, that I use a lot, is to take a screenshot. I use command-control-shift-4 ( ⌘⌃⇧4) to send a selection of a screen image to the clipboard, and then I paste it. You can get 2400 pixels across or more depending on the zoom, and that's a full page image at 300 dpi. This is also really fast.