How do we get knowledge from Imagination?
That we do - or can do - this, was a belief shared and elaborated by Samuel Taylor Coleridge, Rudolf Steiner and Owen Barfield. But how this has happened and might happen is hard to explain - at any rate these three men found it hard to communicate what they meant.
So I will try another tack.
My suggestion is that we can understand Imagination by comparison with Love (as Christians distinctively understand Love - that is, as the primary and most important reality).
Love is not an emotion - it is a relationship. Hence Love is a structuring thing - relationships structure reality, and structure may become known. To know that there is structure is to know some thing; to know something of that structure is to know something more.
Hence, structure is a form of knowledge.
And Imagination has a structure, and it is the structure (and usually not the content) of Imagination that is knowledge.
So, it is the structural relationships of Imagination that constitute the knowledge.
Relationships are between entities - entities including both human and non-human, living and (what are regarded as) non-living.
The knowledge element of Imagination is about the world of relationships - and it is the reality of these relationships, and the specifics of these relationships, that provide meaning and purpose by binding us into relationship with a structured reality.