An image-processing system and a method for controlling the same, including an image-scanning device obtaining image data by scanning data written on a document, an image-processing device processing the image-data item and outputting as an output-image data, and a user interface including setting conditions of the scanning and the image processing, setting an item having a limit value, so as to determine whether or not, at least one of (1) the size of the processed image data, and (2) a time period from when the scanning processing is started to the output, should be limited based on an input from the user interface, changing at least one of the conditions based on the item, performing scanning for the document based on the conditions and the changed condition, and processing image data obtained through the scanning based on the conditions and the changed condition, and outputting the output-image data.