As per Comscore report, JPEG display ads in the US led the market with 42 percent of impressions. While “leaderboard”-728 x 90 in dimension ads were the most commonly viewed display ad by size.
Nearly 60 percent of US display ad impressions was standard GIF/JPEG type, in April. JPEGs contributed for 42.4 percent of ad impressions. GIFs contributed for 14.1 percent. 40.3 percent of all display ads was combinedly represented by flash and rich media. 3.1 percent of ad impressions were acconted by PNG ads.
Very common ad sizes were medium rectangles at 18.6 percent with 300 x 250 in dimension, leader boards at 18.3 percent with 728 x 90 dimension and buttons at 14.7 percent with 120 x 90 dimension.
There is similar representation between the display ad market and the most common add formats, with the banners accounted for 23.1 percent of impressions, 22.7 percent rectangles and 22.1 percent non-standard units.