You can find the option to upload your Imagekind product feed under Account Settings>Product Feeds
Enter your Imagekind screename (Your Imagekind screenname is your user name on Imagekind and can be found by going to your Imagekind profile page. Your screen name is listed directly under your full name where it says “Screen Name:”. Please make sure to enter your Imagekind screen name correctly, or your feed will not show up.) in the box next to 'Feed file prefix'.
From the 'Your feed provider' dropdown select Imagekind.