User experience designers often employ natural landscapes as background imagery in e-commerce user interfaces (UI). However, at this stage, there is only limited work on how nature imagery in UI design affects user perception and behaviour. In this paper, we present a qualitative study involving semi-structured interviews into the use of nature imagery in UI design. Our study builds on theories in environmental psychology and seeks to develop a theoretical framework for the role of nature imagery in user perception and behaviour. Further, building on the expertise of user experience practitioners and end users, we seek to develop theoretically-grounded design guidelines for the capture, selection, and integration of nature imagery in e-commerce UI designs.