That’s weird, sometimes it doesn’t work, but mostly it does now.
But when it works it greatly reduces the number of flavors on my clipboard.
Before, with the webpage copied (16 flavors):
After the KM action (6 flavors):
Apparently it merges the text with the flavors it understands and discards the others. However, the Rich Text flavors still hold the images from the webpage copy.
Yes, my test was with Safari. It maintains the images after merging because of the RTF flavors.
I tried it with Chrome: the merging does work, but the clipboard looses the HTML flavor and the two RTF flavors are without images (as you said, the images were only in HTML as links).
Edit, PS: Firefox behaves exactly like Chrome. Opera too.