Here is part of code that will improve look of the generated code. I found this on CRE forum but
should work for regular osCommerce stores.

**** Backup your files first ****

In zip file you will find visual_verify_code.php that should be paste(replace) in catalog/includes/functions/ and new folder "fonts" that should be placed in catalog/includes/. Folder contain 4 fonts that can be changed choice is yours. automatic.gdf is used to start with.
You will have control to: set image height, width, font size, font position, bg color, text color, border color, noise color.
Screen shot is included.
It is not a full package.

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