Border: Thsi is what most people use. A Border as top layer. The graphic displayed on the icon, is underneath.

You can, of course, color your borders:

The "Behind": The behind has to be behind the image you want displayed. You have to use the blend modes available in the layer palette.

(layer blending set to "soft light"; usually lookes like the original image)

(layer blending set to "color burn "; warmer colors; you have to set down the opacity of the "?behind" to at least 20%, otherwise you won't see anything.)

Colored Brushes are also possible.

(layer blend on "color burn ". No opacity chaneg needed.)

TIPP: if you want to see what certain colors look like in preview, choose Image > Adjustments > Hue/Saturation. Move the Hue modulater back and forth.

Mix & Match

I created several of those behinds for you to use. There is the possibility to use several. To position them differently and/or to use different opacity for each layer.