You can easily remove white backgrounds from an image without having to know a lot of photoshop.
First thing, select the layer you want to edit (if you don’t know how, read this quick tip to select a layer in photoshop).
After you have you layer selected, you will see a small FX icon at the bottom of the layers menu:
After you click on the FX icon you will get a dropdown menu, be sure to select “Blending Options” (generally the first option on the menu). This option will open a Layer Style popup showing you the blending options by default.
At the end of the popup window you will see to sliders that will allow you to control how much of the white background you want to blend. By moving the first slider right control to the left you will see how the white background starts to disappear. You can granularly control these little details surrounding the borders of the image by playing with the slider until you get a perfect transparent background.
As you see, this is an easy way to remove any background from your images to use them on your HTML code and have always a perfect background transparency.