Demonstration of USB control of a Nikon D40 using gPhoto2 software in Linux (specifically Easy Peasy, the Ubuntu derivation for Asus Eee PC computers). GPHOTO2 COMMAND PRIMER The D40 can store photos in one of two places: the camera's internal memory or the SD memory card. You can select which one using: gphoto2 --set-config capturetarget=0 # capture to internal memory gphoto2 --set-config capturetarget=1 # capture to SD memory card CAPTURING TO INTERNAL MEMORY If you want to capture to internal memory you have to retrieve the photo before taking the next picture, so the sequence might be: gphoto2 --set-config capturetarget=0 # run this once gphoto2 --capture-image --get-file 2 # snap photo and download file The value "2" is a 1-based index to the file you want. You can list the files by index like this: gphoto2 --capture-image --list-files If you omit --capture-image you will only see one file (index #1), called "/special/curve.ntc". If you include --capture-image the second file (index #2) will be "/store_00010001/capt0000.jpg", the newly-taken photo. You can also capture multiple files, and then download them, like this: gphoto2 --interval=2 --frames=4 --capture-image --filename=photo%Y%M%S.jpg --get-all-files I haven't figured out how to get the camera shooting in quick mode (2.5 shots per second), though. CAPTURING TO SD MEMORY CARD In this case, you can capture as many photos as will fit in the memory card and then download them later by any means (including using a <b>...</b>