InstantMask

InstantMask is an interesting application. With it, you can extract a certain part of an image by removing the background and keeping only the part that you want.

Because of this, InstantMask is one alternative to more advanced image-editing tools like Photoshop, which include similar selection tools.

To use it, just choose the object you want to extract from the image with the green brush, then select the border with the red one. If you do this correctly, you can see how the application will remove the background by clicking on 'preview.'

InstantMask supports JPG, BMP, and PNG formats. It saves the final results as JPGs.