Background Supporting healthy lifestyle changes is a key aim of cardiovascular and pulmonary rehabilitation programs. SMS text messaging programs have demonstrated effectiveness in cardiovascular disease risk reduction, weight loss, increasing physical activity, and smoking cessation. The optimization of SMS text messaging programs may deliver greater population benefits as mobile phone use becomes ubiquitous. Visual messaging (ie, image-based messages) has the potential to communicate health messages via digital technology and result in enhanced engagement. Objective This study aims to determine and understand patient preferences for lifestyle-focused visual text messages that support cardiovascular and pulmonary rehabilitation. Methods A discrete choice experiment was conducted in a 4-stage iterative process to elicit patient preferences for visual message features. Attribute and level development yielded 3 attributes (purpose, image type, and web address), and 16 choice sets were subsequently constructed according to a full factorial design. Patients participating in cardiovascular and pulmonary rehabilitation were surveyed (on the web) for their preferences regarding the visual message choice sets. Respondents were asked to choose among 16 pairs of visual messages regarding key lifestyle behaviors, namely, physical activity and nutrition. The data were analyzed using a conditional logit model. Results There was a total of 1728 observations from 54 unique respondents. Two factors that were associated with patient preference were gain-framed purpose compared with no purpose (odds ratio [OR] 1.93, 95% CI 1.40-2.65) and real images compared with cartoon images (OR 1.26, 95% CI 1.04-1.54). A loss-framed purpose was less preferred than no purpose (OR 0.55, 95% CI 0.42-0.74). Overall, patients preferred positive images that were colorful and engaged with text that supported the image and had a preference for images of real people rather than cartoons. Conclusions A discrete choice experiment is a scientific method for eliciting patient preferences for a visual messaging intervention that is designed to support changes in lifestyle behaviors. SMS text messaging programs that use visual aids may result in greater patient satisfaction by using a gain frame, using real images, and avoiding a loss frame. Further research is needed to explore the feasibility of implementation and the health and behavioral outcomes associated with such visual messaging programs.