How to cluster images based on meta-information in tags
Yes, this has been studied, but the images seem to be completely irrelevant.

What you have is a set of texts, and you want to cluster them based on similarities.  You simply want to do text clustering.  A very simple way to start is to create a vector that represent each of the words.  Suppose that you have 1000 words.  Sort them, and you have a 1000 dimensional vector.  Now, each text (metadata) is represented by a vector with a 1 in position $i$ if the $i$th word is in the text and 0 otherwise.

Do clustering on these vectors as you normally would, you can easily start of with $k$-means clustering.