A system based on mobile phones with built-in cameras has been developed for the postoperative management of patients sent home after day surgery. The system allows patients to send pictures and pulse oximetry measurements to a hospital server in a few seconds. Health professionals can then see what patients are describing and make a more objective estimate of the patients’ status. Over a five-month period, a total of 49 patients used the system. A total of 222 images were sent, the average image delivery time being 29 s (SD 11). In nine cases (18%), the availability of images modified the treatment, and a visit to an emergency unit was avoided in eight of them who had blood-stained dressings and normal haematomas. The patients who had their treatment modified sent more images (an average of 5.4/patient) than those for whom images confirmed the correct treatment (3.1/patient). Each telephone call lasted for a mean duration of 18 min (range 8–34). The patient satisfaction data showed that all the aspects studied were evaluated in a very positive way, with 96% of the patients completely satisfied with the attention received by the mobile health application.