<query>
    <method>flickr.photos.search</method>
    <api_key>d0c3b54d6fbc1ed217ecc67feb42568b</api_key>
    <tags/>
    <user_id/>
</query>

<query>
    <method>flickr.photos.search</method>
    <api_key>d0c3b54d6fbc1ed217ecc67feb42568b</api_key>
    <tags/>
    <user_id/>
    <tag_mode>all</tag_mode>
</query>

Use AND condition when multiple tags are specified
Use AND condition when multiple tags are specified
