Adding Borders
Here is an easy way to add borders to your images in Paint.
Step 1: First open the image you want to add a border to in Paint. Here's the one I will use:
Step 2: Then click on the
line tool, which looks like this:

. Select the thickness and color of the line.
Step 3: Now go all around your image and add a line at the edges. Zoom in on your image if necessary. Here's my result: