Stained Glass Effect

Open your photograph in Photoshop

File>Place Embedded your zentangle scan on top of your photograph

Stretch or Shrink your image using Transform (Control-T) then hit Enter or the checkmark to lock it in.

Change the blending mode in your Layers Panel to Multiply.

Add a layer mask to the scan layer. (the rectangle with the circle inside it)

Right click on the layer name and RASTERIZE the layer to make it paintable.

Make sure you're on the thumbnail and not the mask when you start painting. Choose a color and click it inside the area to be painted.