[header] How to remove the background using a layer mask in gimp [title] Open up your image in gimp. [step] This picture of a toddler will be used here. [title] Click on the brush icon and set it to a' softish' setting. 
[step] You don't want it to be too hard or too soft. This will keep your edge from being too hard so that your subject will blend in easier in whatever scene you might put them in.