SEO Basics - Alt & Title Tags
When using alt tags you have to make sure that it matches or closely relates to the images content. If you assign image alt tags that have nothing to do with the image that is being assigned or have obviously stuffed keywords your content could be ignored or in a worse case scenario count negatively towards your pages ranking.
Link title tags should be assigned so that they relate to the content being pointed to and do not contain stuffed keywords. In most cases a couple words of very short description will do. Making a very long title tag or stuffing in too many keywords can affect the links relativity to search engines making the link pretty much useless.
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