| To make a background of a button or image transparent so there is not a white box surrounding it on a web page background, first choose transparent when opening a new Photoshop file. |  |
Next, when you select "Save for Web" select the transparency box. Under Matte, choose Other.
Then in the Color Picker dialog box, select "Only Web Colors" and type the number of your web page background color in the #box. If you are using a textured background or a background image file, select the color that is most primary in your image file.
When you have selected your background color, it will appear in the Matte box and be used to create drop shadows or other effects.