When you save artwork as an Adobe Illustrator (AI) document with the Create PDF Compatible File option selected, the preview that appears in Adobe Bridge is of the entire Artboard (typically a letter-size page). To make Bridge preview only the artwork, and not the entire page, do the following:
1. In Illustrator CS3, double-click on the Crop Area tool, or press Shift-O (the letter O, not the number zero) followed by return or enter.
2. Choose Fit Crop Area to Artwork Bounds from the Preset drop-down list at the top of the Crop Area Options dialog box.
3. Save the file normally, with the Create PDF Compatible File option selected.
This will make Bridge previews of your Illustrator files larger and more useful.