The Replace Image functionality lets you remove one image and put another in its place. Once inserted, you can use the full set of image editing tools to correctly position and size the new image.
To replace an image:
On any ribbon tab, in the Tools group, click the arrow beneath Copy Text.
Click Edit Text & Images .
Do one of the following:
Double-click the image.
Click the images, and then click the Format context tab in the ribbon.
On the Format context tab, in the Adjust group, click Replace .