Working with hallucinogenic images during meditation

I often experience hallucinogenic images during meditation. I don't believe they are caused by lack of sleep as they occur irrespective of my state of tiredness. Typically the sequence goes 1. Meditating with a lot of discursive thoughts 2. Discursive thoughts settling down 3. Commencement of strange dream like images 4. If i go through this then thought drops away and it the start of a calmer more focused meditation I don't always get the images but if I do then they are very difficult to work with. They are more dominating than the discursive thoughts and more difficult to see them for what they are. However I know that if I can go through this stage then meditation really becomes a lot easier and more pleasurable afterwards (fourth stage above). Has anyone got any advice about working with these kind of hallucinogenic images? Is there any advice either from traditional texts or contemporary teachers about them? Is it just me?