I would do it like this:
Write your text in one layer.
Apply Your image in a layer, above the layer that contains your text.
Now hold down the key “Alt Gr” while you slowly moves the courser over the line that separates the 2 layers in the Layers-window.
When the courser changes from a hand to a funny looking arrow, then click. (Funny looking...hmmm)
The line that separates the 2 layers will become dashed an the image will be applied to your text.
Funny loo...whatever