Select one of the following options:
Create a spacer image file creates a GIF image to use as a spacer image, and allows you to select a folder in which to store the spacer image file, such as your sites images folder. This is the recommended option, unless youve already created a spacer image file for your site.
Use an existing spacer image file allows you to specify an existing spacer image file to use in autostretch tables. The spacer image should be a single-pixel transparent GIF.
Dont use spacer images for autostretch tables specifies that Dreamweaver should refrain from automatically adding spacer images to tables. (This option does not appear if youre inserting a spacer image without making a column autostretch.) If you select this option, fixed-width columns in your layout might collapse to a small width, or even to zero width; spacer images help maintain the structure of your layout as you originally drew it. Use this option only if youve already placed enough content in your fixed-width columns to prevent them from collapsing, or if you have already added spacer images manually.