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WordPress.com also has a built-in method for inserting images for Amazon.com products. If you place the URL of an Amazon product on a line by itself in the Visual Editor, WordPress.com will automatically convert it to an Amazon link complete with image. This also works in blog comments. Any affiliate URLs you have used will be retained.
Please keep in mind that blogs that are created for the sole purpose of posting Amazon.com or other affiliate links are not permitted on WordPress.com and are subject to suspension. You may feel free to use affiliate links to recommend products about which you are blogging or which you are reviewing on your blog, but excessive linking to affiliate networks is not permitted under our Terms of Service and/or Advertising Policy.