I want to create a layout like this with html & css for thumbnail listing.

I want to fill a DIV with thumbnails & exclude a portion of that DIV from content & fill it with some other content;
Is it possible? How?
Yes, use a floating layout. You could float:left; on everything in CSS, clear:left; on the 7th small div. Note that you may need to hold open the div that you're putting this HTML inside. For backward compatibility I use an empty div at the bottom and clear:left; on it. You may consider a background image on the larger div to the right to create that border effect.
z-index.floatordisplay:inline-blockis the answer, without usingposition:absolute.