change:
document.getElementById('captchaImage').src = "WA_ValidationToolkit/WAVT_CaptchaSecurityImages.php?noisecolor=" + "<?php echo $WAGLOBAL_Captcha_Noise; ?>" + "&bgcolor=" + "<?php echo $WAGLOBAL_Captcha_BG; ?>" + "&textcolor=" + "<?php echo $WAGLOBAL_Captcha_Text; ?>" + "&transparent=" + "<?php echo $WAGLOBAL_Captcha_BG_transparent; ?>" + "&characters=" + "<?php echo $WAGLOBAL_Captcha_Characters; ?>" + "&width=" + "<?php echo $WAGLOBAL_Captcha_Width; ?>" + "&height=" + "<?php echo $WAGLOBAL_Captcha_Height; ?>" + "&font=" + "<?php echo $WAGLOBAL_Captcha_Font; ?>" + "&time=" + now.getTime();
to:
document.getElementById('captchaImage').src = "WA_ValidationToolkit/WAVT_CaptchaSecurityImages.php?noisecolor=99CCCC&bgcolor=FFFF00&textcolor=333333&transparent=false&characters=6&font=Fonts/MYTYPE.TTF&time=" + now.getTime();