cleaning up images

images/dtmf_0_off.png

images/dtmf_0_on.png

images/dtmf_1_off.png

images/dtmf_1_on.png

images/dtmf_2_off.png

images/dtmf_2_on.png

images/dtmf_3_off.png

images/dtmf_3_on.png

images/dtmf_4_off.png

images/dtmf_4_on.png

images/dtmf_5_off.png

images/dtmf_5_on.png

images/dtmf_6_off.png

images/dtmf_6_on.png

images/dtmf_7_off.png

images/dtmf_7_on.png

images/dtmf_8_off.png

images/dtmf_8_on.png

images/dtmf_9_off.png

images/dtmf_9_on.png