The current image saving process has two main disadvantages:

1.) It's tedious as it takes quite long to manually select an image
2.) it doesn't save the image in its original resolution, forcing you to zoom in as far as possible to get a high resolution "screenshot"

Evince offers the ability to directly extract an image in its original dimensions by either dragging and dropping it into a file manager or choosing the "save image" option from the context menu (see the link above for an example).

Okular's advantage is that the image selection dialogue also caters to vectorized images, which Evince can't handle.

Combining Okular's image selection method with Evince's image extraction feature would provide the best out of both worlds.

Reproducible: Always