BMP is structure for storing bitmap photographs. In this format, you are able to only save bitmaps monolayer. For each pixel in different files could arrive different quantity of bits. For the advantage of downloading all images just after conversion are stored inside the typical zip archive. BMP is format https://johnathanzvoft.blazingblog.com/6188650/an-unbiased-view-of-itspdf-for-pdf-to-jpg-file-conversion