Remove white background around an image on my website

On my website page, I’ve inserted an image in a php scripts and it has a white box around it. Image is saved in my “images” folder in my server.
I know how to remove the white back ground (Adobe Fireworks), so you just see the image.
What I want to know is now that I have my image with no background, how do I make it were the image does NOT show a white box on my webpage?
Thanks in advance,
Scotty