While some users may have a lot of available space, some users on Windows tablets only have 32GB - 64GB which some of that space is taken by the OS and other programs on the tablet. We also chose to not print in color to make the program faster. Clicking throught the days and loading up color images and the xml data could take significally longer depending on the size of the log image. Also black ink is cheaper than color ink cartridges :)
In addtion our certified fax feature also has to send the image along with some XML data, so using smaller images helps send the logs faster.
Hope this information helps!