The name of the session variable where the extension save the text of the image created. To be safe the text cannot ne put inside the page form so the extension generate a random text and save the value in a session. When you must validate the form you must compare the value of this session with the value of the form field.
The image you want apply the extension. You must insert a void image tag in the page and give the name propertie.
Like this example
The width of the generated image
The height of the generated image
The length of the random text in number of characters
The distance betwenn the chars.
Rnd top margin:
If checked put each chars of the text to a random distance from the top of the image.
Apply a graphics effect to the image.
The effect available are:
- random foreground lines
- random background lines
- sketch and random bground lines
Use this effects to make more difficult for text recognize application
The number of lines when you setup a noise effect
Min line length:
The minimum length of the noise line. The length is random