Preparation: Place a USB drive in the android (robot) labelled USB port
Note: If ES File Explorer starts automatically, please close application before proceeding.
Select the [Apps] button on the lower right of the float menu.
Choose the [Gallery].
Choose the desired picture or folder (e.g. Screenshots).
Keep the picture or folder pressed until the share button appears (left from the trash can icon) and select the [ES Save to...] button.
By default this will be the USB port labelled with the Android robot (mnt/usb/sda1 path).
If the desired path is displayed press select and the following screen will be shown. (2 files in this example).
When copying is finished, the files are saved to your USB drive.