extracting odd-shaped parts of figures

I have some photos of instruments, but there is a lot of stuff in the background cluttering up the photo. I want to crop out the instruments and arrange them in a single figure.

1. Import the figure at high resolution into photoshop
2. In the layer dialog drag the layer down to the bottom (the icon for creating a new later) to create a copy of the layer.
3. Make a layer in the middle of the two layers and Fill it with white in the background - when you crop out the image, you want a white background, but if the original image is in the background you won't get that.)
4. Use the Lasso tool, "L" to outline the shape you want to keep. You can click "enter" to complete the polygon.
5. cmd-shift-I to invert to select the area around the shape.
6. Delete to remove the area around the shape.
7. Save as a jpg.

vs.

photos from M. Tivey