Here is the code from my file:
<img 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; ?>" alt="security code" />
I don't see too many values reflecting my changes to the WA_Globals.php file. So not terribly clear how one changes this code as one way to modify the Captcha image.