Using less Pins to connect a 3.2" LCD Display

I have a very simple yes/no question, here it is: so I found this LCD Touch 3.2" Display with an SD Card Slot. All together this thing uses much pins. Therefore they sell these LCD Shields for arduino megas. I read that i can read bitmaps from the SD card an show them on the screen. My question is now: can I simply draw bitmaps via a command and dont use all the data pins? I only have a nano so that would be good. In my (hopefully not so wrong) world I should be able to use only the Command, Touch, Ground and VCC Pins. Is that correct? thanks, :) Marius (pizzadejamon)