Turn any photo into a dot grid artwork with these Photoshop actions. You'll get great results with dots that change size. They get larger in brighter areas and smaller in darker areas. Free download available.
Hide all the parts of the mountain 1 layer using layer mask but keep some parts above the waterfall 2. Here you can see how I covered it over the waterfall 2 layer.
As you can see in the previous step I've kept some parts of waterfall 2 (hard edges) and to blend it we'll use the same waterfall 2 image. So place the waterfall 2 image again (above waterfall 2 layer) and this time transform it shown in the image below as we only want the bush parts of this image. Also, name it 'Waterfall 2 again'
Here you can see how I placed it after transforming it.
Hide all the parts of 'waterfall 2 again' layer using layer mask but keep the selected parts (see the image below) of 'waterfall 2 again' layer to blend it with waterfall 2 layer.