Endless Slideshow Screensaver Pro allows you to add a customizable frame to all your photos in a slideshow. You can select the frame color and set different widths for every frame side if you want. This can be used to create a "polaroid photo frame", for example. All frame settings are available in the [ Frame ] section of the [ Viewer ] tab:
So, if you want to see a frame around your photos in a slideshow check the [ Draw a frame around every picture ] box first. This enables the rest of the frame settings and you can click the [ Color ] box to choose a color for your frame. After that, you can set the width or height of every frame side in pixels. The result may look like this: