David, how would putting text not related to the image into a layout image not be considered spam? Under 501, a blank alt tag is supposed to be used for design elements that do not convey relevant content to a sighted visitor (to do otherwise is to hinder non-sighted visitors to your site, placing them at a greater detriment when visiting than is experienced by the sighted, and a clear violation of the law). Also, my understanding was that search engines will at some threshold stop counting keywords. Once you oversaturate the page with a certain keyword, the engine either stops counting, or worse starts penalizing by deducting value from that word as they perceive it as spam.

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The best way to learn anything, is to question everything.