How to Format Picture Border in Word
How to Add Picture Borders in Microsoft Word
Add a border to a picture
The Picture Styles gallery offers many preset styles that make it easy for you to add a special sort of border with one click.
Select a picture you want to add borders, then click on format going to the picture tool. Now click on "Picture Border", here you are able to change the image line color. You can also change "Weight" for line thickness and "Dashes" for border style.