thanks a lot sunil....
Indirectly to SatDa too...
he showed me that trick...
we never used to scroll down & think that those displayed above the advt. are the only options....(and they were just thumbnails)
the "real" link of full-sized pic was always hidden down, below the advt...
Imageshack benefits from these thumbnails sized pics, as on clicking those thumnail pics in any post, a new browser window opens up leading to imageshack's website....
thus it's number of hits/website visits increases, and so, its advt revenue...
Imageshack even "recommends" to use thumbnails, as this would "reduce their bandwidth load"