How to remove background from an image with Gimp?
There are several ways, like always, like in Adobe Photoshop or the like. One that comes to mind that used to work: use magic wand to select the background (and interior parts if you want them to go away) , do whilst shift pressed to add more areas, hit ctrl+i to invert selection, and without deselecting (so it gets placed in same area) hit ctrl+v. Then in layers window right click on that strange new layer created, and in the context menu that pops, select "new layer", it will be only the pixels you want and the rest is transparent. Now you'd delete the background layer (your original scan)
Another possible way: Zoom the picture and use the free selection tool to select the parts you want to keep, then invert the selection and remove the selected background (if you have transparency on the layer, if not you first have to add an alpha layer to your current layer), I mostly use this method over the fuzzy select because most times I achieve better results.
I recently found another way to do this, a plugin called GML-Matter, in a few words: You select your parts to keep with a pencil-like tool, fill the area inside(or outside) the selection and then press "Matte" (I think it is called like that in english, I use another language for GIMP and I dont know if the GML-Matter has different language sets) and voila: It will give you the part you filled with transparency added to the rest (as for the first way you need transparency on the layer)
-Edit: Sorry I just saw that this post is a few years old, but it showed up in my stream so I didnt look on the date