I was going to say that I'm pretty sure you can already copy most things from one project to another without too much difficulty if you use the ctrl+c / ctrl+v setup.
I'm not sure how being able to copy and paste it from external sources would be any more helpful than importing it from either the popup image window or dragging it into the location you want it to be is. They've already revamped the image setup so that you can see the folders in the popup image chooser, and you can easily drag an image from it's location right to the folder you want it in inside the app.
As for images on the web, I personally wouldn't ever use that feature as I always end up having to edit them to resize, clarify, recolor, etc. so there's no point to it most of the time. Very very few times do I use an image directly from the web as is. Maybe that's just me, but for me importing or dragging directly from the web wouldn't be useful and I can think of a whole lot better places that time could be spent right now.