How could I for example add in the Google search the name of the director so that I am sure I will actually find images only related to the movie, and not other ones? Is it possible?
No, there's currently no variable for director. Generally speaking, it would be nice to have more variables to use in web searches. I wonder, however, if it would really help much in the case of Google Images. Including director will, of course, make it more likely the resulting hits are the movie in question, but it will also eliminate sources that don't happen to mention the director. I suppose it would still make it easier—you can always remove the director and refresh the results if the results are too narrow.
Have you tried
TinEye, as suggested
here? Use Google Image to find the image you want, and then TinEye to find the best available version of it.
We could have the browser integrated into PVD...
I imagine full integration probably is too complicated (or would be a pain to maintain as browsers change). I would be happy if I could enter images to PVD via the clipboard (i.e., right-click on any image/place-holder in PVD and select "paste" to replace/add with the one from the clipboard). That's not quite as convenient, but would be more versatile because we would be able to copy the image from anywhere.