GIMP Version: 2.8.4
Operating System: Windows
GIMP Experience: Beginner Level

---

I am trying to add a background to a photo using a second picture. I have tried a couple of methods, but neither seem to work. One that would work best, if it did, is dragging the background photo as a layer, the adding the foreground photo and erasing the areas of the foreground that aren't needed. This seems to only erase both, even though the foreground photo is highlighted in the layers box. Is there something else I am missing?

add white layer mask to the top layer and painted black to the mask to remove the background of the top layer

Your top layer hasn't been set to be transparent, so when you use the eraser you get the default background color instead of transparency. To set it to be transparent where needed: "Layer>Transparency>Add alpha channel". Then the eraser will work as you think it should.

okyl168's suggestion to use a layer mask has value, this is an improvement on the eraser method where you can easily indicate where the layer should be transparent or opaque just by painting (so you can restore opacity later without having to undo unrelated erasures). Here is a good explanation on layer-masks: http://blog.patdavid.net/2011/10/gettin ... masks.html

Very good example ofnuts.

Excellent. Thanks.

This might be a needless reminder, but since I keep doing it (:p), I thought it's worth mentioning. Always double check you have the right layer selected when you start erasing. Otherwise you end up having to start from scratch if you don't notice until too late on the undo list.

Thanks for the note about layer masks. I do a lot of layer work and have been erasing. I'll look at the masks for the future, though I do wonder if the file size wouldn't be better without.

Thats why we have the undo tool. very handy...

Glad it's not just me . The only really problematic times is when it's not obvious I've worked on the wrong layer until much later.