Could multiple uses of the same keywords in image alt attributes hurt SEO?

Question

Let's say on an e-commerce site that sells unique pens, on a particular pen's product page, the image of the pen has an alt attribute value of "unique red-striped pen"... and another product has "unique blue-spotted pen", etc... The keywords across all products being "unique" and "pen", which would also be helpful when it comes to SEO.

However, if the person just goes to the general "unique pens" category page and sees a list of thumbnail images, each with the words "unique" and "pen" in the alt attribute, would that potentially have a negative impact with regards to SEO by having the same keywords too many times?

Answer 1

If the category page can be crawled (e.g., it's not dynamically generated), using the same keywords in all the alt attributes on that page might be considered to be keyword stuffing by search engines like Google.

Google's Penguin update specifically targets things like this which might be construed as "blackhat" techniques. So even if done inadvertently, your site might be penalized. For more on this, see this review on the subject at Google's Webmaster Help forum.

Also, see the bottom of the section named "Create great alt text" here: Google Webmaster Tools: Image publishing guidelines