PNG/renders are image that have a transparent background.
What You Need
- Photoshop (I use CS4)
- General Knowledge about the Program
1) Select an image the choose the pen tool from the toolbar.
2) Start selecting the area that you want the background to be removed from.
3) When you're done, connect the last anchor (the point) to the first one.
4) Go to the Path tab. If you don't have one, go to Window ---> Paths.
5) On the path tab, you will see a layer like section. Right click it and choose Make Selection.
6) Make the settings like this image below:
7) It will now be selected like this:
8) Press "Delete" on your keyboard. Delete ALL the layers beneath your extraction (image).
9) To check if you extracted your image right, make a new layer (Layer --> New Layer) and color it black. Place the layer beneath your extraction (image). If there are any white spots or aspects that you want to further remove or fix, do that.
DON'T FORGET TO DELETE THE BLACK LAYER ONCE YOUR DONE!
10) After deleting the black layer, go to file --> Save As ---> TYPE FILE NAME (and select .png).