1. A system for facilitating routing of media items between user devices, the system comprising: a routing computer system comprising one or more processors programmed with computer program instructions that, when executed, cause the routing computer system to: obtain images or videos from one or more sources; obtain, from the images or videos, metadata associated with the images or videos; perform object recognition on the contents of the images or videos to identify individuals or other objects in the images or videos; assign first and second images or videos of the images or videos to a first media item group based on (i) the first and second images or videos having similar metadata and (ii) the object recognition identifying an individual or object in the first image or video and an individual or object in the second image or video that are similar to each other; cause the first image or video to be provided to one or more user devices of one or more users based on (i) the assignment of the first image or video to the first media item group and (ii) the one or more users being associated with the first media item group; determine a group criteria for the first media item group based on the assignment of the first and second images or videos to the first media item group; generate one or more advertisements based on the group criteria; assign the one or more advertisements to the first media item group; cause the one or more advertisements to be provided to the one or more user devices of the one or more users based on (i) the assignment of the one or more advertisements to the first media item group and (ii) the one or more users being associated with the first media item group; detect a change in lighting conditions in the first image or video; and generate one or more suggested actions to be taken by the one or more users based on the detected change in lighting conditions in the first image or video.