The Image Properties dialog box enables you to set properties for a new image, or modify properties of a  selected image.

This dialog box contains the following sections:

In the Size section, set width and height of an image (in pixels).

In the File Format section, choose either JPEG or GIF format for an image. If the GIF option is selected, you may also define the Color Count attribute:

The Background Color section enables you to set a  background color for your image.

You can set the background color to be the same as image worksheet color (see the Preferences dialog box). Choose the Same as image worksheet color radio button. To set a custom background color, click the Select a different color radio button, and choose a color by pressing the black colored rectangle on the right . The Choose Color dialog box opens up. Choose a color from the palette.
To make a background transparent, choose Make it transparent. This feature is available only for a 256-color GIF format.

If you have been using a photograph or a detailed artwork, you may want to use a JPEG format instead. JPEGs provide crisper and cleaner images on a web page. However, they are about two to three times larger in size (memory) and take longer to be viewed by a viewer.

Select Encoding Method:

Select the Quality Factor. The smaller the file, the lower is its quality. The larger the file, the higher the quality is.

Changing properties of an image resource will effect  adequate modifications for the image throughout your site project.