وَالِاسْتِعَارَةُ التَّخْيِيلِيَّةُ حُسْنُهَا بِحَسَبِ حُسْنِ الْمَكْنِيِّ عَنْهَا
The beauty of imaginative metaphor depends on that of its associated implicit metaphor.
An imagined attribute ascribed to the subject depends on the hidden comparison that makes its attribution meaningful. If the basic likeness is unsuitable, its added imaginative feature does not become eloquent merely because it is striking.
The underlying comparison must therefore be assessed first; then one asks whether the associated imaginative details strengthen the image or turn it into forced ornament.