Let's use a typical group photo to illustrate the steps:
This photo is what u will normally have. Almost everyone wears the same color clothes and the background is not so uniform to be selected out.
We are going to extract the boy in from, with blue jeans.
Step 1
Select Image->Magic Extractor from the pull down menu. You will now be presented with a new pop up window, the Magic Extractor window.
Step 2
Using the foreground brush tool (the 1st button on the left), dash or dot on the inside edges of the person you are extracting. Use short dashes, or even dots, if you are at very hard to define edges. Zoom in closer will help. By the way, these will show up as red dots and strokes on the image. Don't worry about it, it is not affecting the original image.
Step 3
Continue using the same foreground brush, use long zig-zag strokes to draw within the image you are selecting.
Step 4
Using the background brush tool (the 2nd button on the left), dash or dot on the outside edges of the person. Same rules applies here, try to get very close to the edges. Zoom in and use short dashes or dots if you are at hard to reach places.
Step 5
Continue using the BACKGROUND brush tool, draw long zig-zag lines on all the rest of the image you do not want.
The picture should look like this now:
Step 6
Click on Preview button to see the possible result. You should see quite a nicely extracted image of the boy.
Step 7
Repeat any of the paint foreground or paint background steps above if you have to. However, if you have followed closely, you can safely click on Ok button now.
The image which I have at this stage:
Step 8
You should see some unwanted patches here and there, but quite far away from the image you want. They can be easily removed, or in my case, I just crop out the boy I want.
Finally use a small soft eraser tool to clean the edges of the image extracted.
The result:




































