The Visual Index Image Format
with Overlay (light,) 4x3 thumbnails, 200px thumbnails, three columns (called "counter" in Exhibit Options dialogue box), titles off

In ADMIN > FORMATS > OVER AND OVER, you can manually adjust the spacing between the thumbnails (right margin and bottom margin), the background color of the overlay (light or dark)

http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_taxonomyposter_825.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_workbookwriting_825_v3.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_workbook_withmap_825.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_taxonomydetail_825_v3.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_mapdetail_825_v3.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_posterdet_825_v2.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_fieldguidedet_825_v2.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_pocket_825_v3.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_mapinbook_825_v3.jpg
http://thepresentgroup.com/indexhibit-tutorial/files/gimgs/th-18_fieldguide_withmap_825.jpg