Make a .png file WITH TRANSPARENT BACKGROUND for the products

Once you've opened the file you're about to edit select the pen tool.

With the pen tool you're going to outline the object. I'm not sure how familiar you are with photoshop so I've added in a couple of notes! 

Also, it always looks a little better if you cut into the object by a couple of pixels rather than having a white 'halo' effect around the edges.

Once you've outlined the item, right click on the image and select make selection. In the pop up window make sure you have the following settings:

• Feather Radius: 1 pixels / Anti-aliased: ticked

Delete the background. 

• If you're finding that you're deleting the object instead of the background press 'cmd + shift + i' which will select the background.
• If you're finding it won't go transparent double click the background layer and select ok to unlock the layer.

Once you're happy with your image select 'Save As' and change the format to 'PNG'