Online video advertising is now an increasingly important tool for marketers to reach and connect with their consumers. The purpose of this study was to empirically investigate the impact of video format on online video advertising. More specifically, this study aimed to explore whether online video quality and image size influences viewer responses toward online video advertising. By conducting an experimental study on YouTube, the results suggested that enhanced video quality of online advertising may have an important impact on effectiveness of the advertising, and the concept of presence is a key to understanding the effects of enhanced video quality in online advertising.