The Captcha Generator comes with a number of variables that allow you to decide how hard the captcha image will be to decode.
The CatchaGen script allows you to set various options for your images including :
Turn Gradient background on/off
Use noise over the image rather than pattern
Use Same font for all text or vary the font
Use Same font color for all text or vary the font color
The first image above is probably the easiest image to decode, it has a single colored background,and the font for each letter is the same style and color, this means that many that attempt to decode could look at the colors and calculate the text. The decoding is made more difficult though by the pattern that is laid over the whole image which is the same color as the text.
The second image above is slightly harder as the background image has a gradient making the decoding slightly more difficult as the number of colors in the image has increased.
The third and fourth images are slightly different again. The difference between these and the previous two images is that instead of using a pattern over the top, 'noise' is added instead.
This adds even more color to the image and the text in particular which could again make it harder to decode, but depending on the fonts used, they can prove hard to read to the human eye which is not what we want, however you can ignore fonts that are difficult to read.
Aswell as the using gradient backgrounds and noise or patterns on the images you can also opt to have each letter in a random font as shown on the left.
This increases the difficulty of decoding once more but we can go one step further by changing the color of each letter. This can be combined with using different fonts.
Above is our final example, it has a gradient background with the maximum of 8 characters each in a different font and color.
Use the refresh button below to view various images that can be generated.