Background Postoperative surgical site infections (SSI) are common and costly. Most occur post discharge, and can result in potentially preventable readmission or unnecessary urgent evaluation. Mobile health approaches incorporating patient-generated wound photos are being implemented in an attempt to optimize triage and management. We assessed how adding wound photos to existing data sources modifies provider decision making. Study Design We used a web-based simulation survey using a convenience sample of providers with expertise in surgical infections. Participants viewed a range of scenarios, including surgical history, physical exam, and description of wound appearance. All participants reported SSI diagnosis, diagnostic confidence, and management recommendations (main outcomes) first without, and then with, accompanying wound photos. At each step, participants ranked the most important features contributing to their decision. Results Eighty-three participants completed a median of 5 scenarios (interquartile range 4 to 7). Most participants were physicians in academic surgical specialties (n = 70 [84%]). The addition of photos improved overall diagnostic accuracy from 67% to 76% (p < 0.001), and increased specificity from 77% to 92% (p < 0.001), but did not significantly increase sensitivity (55% to 65%; p = 0.16). Photos increased mean confidence in diagnosis from 5.9 of 10 to 7.4 of 10 (p < 0.001). Overtreatment recommendations decreased from 48% to 16% (p < 0.001), and undertreatment did not change (28% to 23%; p = 0.20) with the addition of photos. Conclusions The addition of wound photos to existing data as available via chart review and telephone consultation with patients significantly improved diagnostic accuracy and confidence, and prevented proposed overtreatment in scenarios without SSI. Post-discharge mobile health technologies have the potential to facilitate patient-centered care, decrease costs, and improve clinical outcomes.