If you'd like to move an image, you have a few options.
Move the entire photo container by clicking and holding anywhere on the image, then dragging it to another location. This moves both the image container and the image within it.
Move the image within the container by clicking and holding the hand icon as seen below.
Then drag the image up, down, left or right within the container. Here we've moved the image over to the right, so it's out of the book gutter. This action moves only the image and not the image container.