Considering a site with 100.000+ photos and growing. All photo tags are separated with comma.

Is better to put all photo tags into 1 row or separate?
photoId | tag
-------------
1 | sea
1 | beach
1 | night
33 | cars

SELECT photoId FROM photos WHERE tag='tagname'

OR

photoId | tags
1 | sea, beach, night
2 | cars

SELECT photoId FROM photos WHERE tag IN ('tagname')

Which one is better, or is any other better way?

Thank you