Out of all my years working in zen cart I've never been required to set up a file upload. I know this works and I thought I knew what to do but the truth is that it's not working.

Attribute is set up as a file. After you browse for the image and select one (I am using a very small one), the name of the image appears. When you add to cart, there is no evidence that the file uploaded and sure enough, it hasn't uploaded.

What file controls the uploading of the attribute images? I know that I have the correct version of the modules/attribute.php file in the cart.

The images folder is set at 755 on this server and there's no problem uploading product images. I even checked the configure file to make sure all was fine there.

No dice. It's just not uploading files and I don't know why or where this is in the zen cart file structure to check. Help point the way for me.