[{"template":"one","colors":[{"name":"yellow",images:["img_one","image_two"]},{"name":"blue",images:["img_one","image_two"]}]},{"template":"","colors":[{"name":"green",images:["img_one","image_two"]},{"name":"orange",images:["img_one","image_two"]}]},{"template":"three","colors":[{"name":"green",images:["img_one","image_two"]},{"name":"orange",images:[]}]}]

db.collection.aggregate([{"$match":{"template":{"$ne":""},"colors":{"$not":{"$elemMatch":{"images":{"$size":0}}}}}}])