1. A computing device implemented at least partially in hardware operative in a digital environment in which blocky images at a relatively lower resolution can be converted to corresponding smooth images at a relatively higher resolution, the computing device comprising: an image smoothing module configured to perform operations comprising: obtaining a blocky image including multiple blocks; determining a boundary shape representation of a portion of the multiple blocks of the blocky image; inputting the boundary shape representation to a machine learning system that models at least one relationship between boundary shape representations of blocky images and locations of corresponding smooth boundaries of smooth images; responsive to the inputting, obtaining an indicator that corresponds to the portion of the multiple blocks and is indicative of a location of a smooth boundary that corresponds to the portion of the multiple blocks of the blocky image; and using the indicator, constructing the smooth boundary that is at least part of a smooth image corresponding to the blocky image.