In a previous article we talked about banner standard sizes, one of the most important metrics in banner advertising. Now the second metric in the order of its importance is the file size or file weight. The file size is measured in bytes, often with the kilo- (thousand) or mega- (million) metric prefixes, and it represents the amount of disk space consumed by a particular file.
As with other files, banners (JPGs, GIFs, SWFs etc.) have certain file weights. These files are temporarily downloaded on the users’ computers when they open a web page, so the bigger a banner file is, the heavier and slower to download that web page will be. That made publishers introducing some restrictions regarding the file sizes of the banners they would accept. And that was the first step to introducing a set of universally accepted standards concerning the banner file sizes.
Of course, the IAB again had an important role in setting these standards. So let’s see them:
The recommended initial download maximum file size for all the standard banners is 40 kilobytes (KB), with a few exceptions:
- Half Banner – 30 KB
- Micro Bar – 10 KB
- Button 1 – 20 KB
- Button 2 – 20 KB
- Vertical Banner – 30 KB
- Square Button – 30 KB
Note that these file weights refer to the initial download. That means, a flash banner can have a total file weight of over 40 KB, but anything above 40 KB is dowloaded “in the background” meanwhile the flash ad/animation had already begun.