you can see first design in above image the dotted border.The color is red but you can change it by replacing color code.
Adding border around image
First login to blogger account
Go to template and click HTML
Press CTRL + F and search box this code
above it paste the below code there.
Dotted border
solid border
to change the color replace #ff3333 with your color code.
Few color codes.
save you template and enjoy the style.