This should currently be able to take a screenshot Rigol DS1000E devices. (Tested with 2 DS1102E connected)

rigol_screenshot.py

#! /usr/bin/env python3
import visa


def main():
    # Get list of connected Rigol devices
    rm = visa.ResourceManager()
    device_list = {}
    for device_name in rm.list_resources():
        device_id = ""
        try:
            device_id = rm.open_resource(device_name).query("*IDN?")
        except visa.VisaIOError:
            pass
        if device_id.lower().startswith("rigol"):
            if device_name not in device_list:
                device_list[device_name] = rm.open_resource(device_name)

    # Get screenshot from all found Rigol devices
    for name in device_list.keys():
        device = device_list[name]
        buf = device.query_binary_values(':DISP:DATA?', datatype='B', chunk_size=1152054)
        filename = "Rigol_{}.bmp".format(name.split("::")[3])
        with open(filename, 'wb') as f:
            f.write(bytearray(buf))


if __name__ == "__main__":
    main()