1. Open the image you want to use. I am going to use this below as an example.
2. Make a raster layour by navigating Layers >> New Raster Layer.
3. Fill the new layer with a gradient. [? - Don't understand? Take a look at this tutorial HERE!
4. Now, take a look to the right, underneath the headline Layers. Change the Blend Mode from Normal to Color (Legacy). Do also change the Opasity to whatever you think looks nice.