Understanding mobile users and their behaviors in context, across multiple countries and cultures, is challenging and costly. However, the reward of creating a mobile application that meets mobile users' needs (and is actually used -not deleted within days of being downloaded) is priceless to the user in terms of productivity, the employer by keeping data updated, and the developer by producing a successful application.To develop such applications, mobile HCI professionals need to identify mobile users' daily mobile habits and tasks completed with their devices. To uncover unexpected uses and a range of contexts, we recommend using a photo diary technique in conjunction with other ethnographic methods. Conducting mobile photo diaries will help mobile HCI professionals in their application decision making process, by giving them additional insights into their users that may have been inaccessible or unthought-of before, and visually rich deliverables to share with management.