Querying MongoDB to match in the first item in an array
I believe you want imgs.0. eg, given your example document, you want to say: db.products.find({"imgs.0": "http://foo.jpg"})
Be aware that referencing array indexes only works for the first-level array. Mongo doesn't support searching array indexes any deeper.
You can use dot notation for array indexes:
db.products.find({"imgs.0": "http://foo.jpg"})Here is an excerpt from the relevant documentation for dot notation.
MongoDB uses the dot notation to access the elements of an array and to access the fields of a subdocument.
To access an element of an array by the zero-based index position, concatenate the array name with the dot (.) and zero-based index position, and enclose in quotes:
'<array>.<index>'
Additionally, here is a link to the relevant array documentation.