A real-time cloud imaging system includes at least a frontend device and a backend system. The frontend device generates an instruction message and a ROI (Region of Interest) message, and the backend system is coupled to the frontend device. The backend system has at least a raw image, wherein the raw image has a plurality of images of different resolutions. Each of the images and the raw image are composed of a plurality of tiles. The ROI message corresponds to a region of interest respectively within each of the images and the raw image. The backend system, according to the instruction message and the ROI message, selectively provides a grouping of the tiles within the region of interest of the raw image or one of the images to the frontend device.