There are a few ways to frame a picture with a mat. The most common way is to place the picture face down on the table, and then place the mat on top of the picture. You can then use a ruler to measure and mark where you want to cut the mat. Use a sharp blade to cut along the marks that you made, and then remove the excess mat from around the picture. Another way to frame a picture with a mat is to place the picture face up on the table, and then place the mat on top of the picture. Use a ruler to measure and mark where you want to cut the mat. Use scissors to cut along the marks that you made, and then remove the excess mat from around the picture. A third way to frame a picture with a mat is to place the picture inside the mat. Use a ruler to measure and mark where you want to cut the mat. Use scissors to cut along the marks that you made, and then remove the excess mat from around the picture.