I imported a picture that I edited and removed the background with no problem. Now I want to replace the background with something else. I imported another picture to use as the background but I cannot add it to the edited picture in Layer 1. I am not sure how I can go about replacing the background with something else. If I could put both of those pics in the same list then I should be able to rearrange the layers to make this work but like I said I can't add the 2nd picture to the Layer 1 picture if that makes sense.
Once you have both images opened in Photoshop, simply drag the "new" background layer from the Layers palette onto your masked image.
This will create a second layer in your masked image file.
Than, reorder the layers in the Layers palette by dragging the layers into the desired layer position.