I have noticed that the "Edit (Pencil)" and "Remove (X)" icons are missing after upgrading Wordpress to version 4.3. In previous versions you could always select the image (to show bounding box) and there was a pencil and X above the image. Then you could click the pencil to get to the Image Details where you could change display settings.
Thinking it may be a plugin conflict, I disabled all plugins, but it still was missing. so then I thought it must be my theme, but after switching the theme over to Twenty Fifteen theme, it still was not working. I have reverted back to WordPress 4.2.3, which works.
Is anyone aware of this being a bug, or is there a new way to reach the Image Details dialogue box in the Page/Post editor?