in costycnc.it/cm8 is dimx and dimy ... also need to have same dpi as program that you create image ... so when working with image raster that have pixels , costycnc need to know how many pixels use your program for draw 1 cm ( the dpi)... if costycnc is not set as same dpi with your drawing program ... can interpret the 1cm high or low that 1cm... i hope that understand that dpi is very important