Software on an image-capturing device iteratively captures a visual code in a series of visual codes displayed in a repeating progression on a screen of a mobile device. The visual code was generated from a display block that resulted from a partition of an original data file into a series of display blocks of at least a specified size. The software converts the visual code back into a display block and reads a header for the display block, discarding the display block if it has already been captured, as determined by the ordered identifying block number in a header. The software stops the iterative capturing when all of the display blocks in the series have been captured, as determined by the count in the header and coalesces the captured display blocks into the original data file, using an order determined by the ordered identifying block numbers.