Visual is a mobile app that promotes Visual Literacy (VL) and it was created as a resource for a VL training course for in-service teachers. The VL course performs through blended learning approach and Visual app allows users to experience learning-on-the-move and ubiquitous learning thanks to affordances of mobile technology. The Visual app presents its content in six short units, which are related to the VL course content. Each unit has ten activities, for teachers to do them. Performing activities helps teachers to improve the understanding about the course topics. Each activity shows immediate feedback to users by evaluating if the response was correct or incorrect. Visual app was designed based on user-centered design methodology. This project aims to achieve an effective integration of mobile technology into the teaching-learning process for in-service teachers training in VL.