Changed auto height and media query
@media only screen and (max-width : 480px) {
#recaptcha_challenge_image{
margin: 0 !important;
width: 100% !important;
height: auto !important;
}
#recaptcha_response_field
{
margin: 0 !important;
width: 100% !important;
height: auto !important;
}
.recaptchatable #recaptcha_image {
margin: 0 !important;
width: 100% !important;
height: auto !important;
}
.recaptchatable .recaptcha_r1_c1,
.recaptchatable .recaptcha_r3_c1,
.recaptchatable .recaptcha_r3_c2,
.recaptchatable .recaptcha_r7_c1,
.recaptchatable .recaptcha_r8_c1,
.recaptchatable .recaptcha_r3_c3,
.recaptchatable .recaptcha_r2_c1,
.recaptchatable .recaptcha_r4_c1,
.recaptchatable .recaptcha_r4_c2,
.recaptchatable .recaptcha_r4_c4,
.recaptchatable .recaptcha_image_cell {
margin: 0 !important;
width: 100% !important;
background: none !important;
height: auto !important;
}
}