Search and Search

how do image search engines work?

what tags of the image metadata are used for labelling by search engines…..also do they use captions and other related textual information in the directory structure or the html document containing the image…thanks in advance
k…i think i,perhaps got the answer anyway…….most of the photos uploaded onto a server are cleaned of any metadata…so we cannot rely on that…hence attributes like alt,src…etc in the <img> tag…and data in the neighbourhood of the image that is used to describe it….sometimes also filenames can be used as potential information to construct a label for the image….this data is ofcourse easily available if we have (pseudo) structured data(as html docs) but …this is not the case with pdf’s .etc …perhaps this is the reason image results often lead to links of html pages …and rarely to any pdf..etc

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