Hobbes: Imagination and Memory

In Hobbes Leviathan, he makes the statement in chapter ii, subsection 3, that "imagination and memory are but one thing, which for diverse considerations hath diverse names." This statement is interesting because it implies that all memories are decaying or imperfect imaginations of past events, but this also implies that all imaginations are forms of memories, twisted, combined, or lacking perfect accuracy. Is Hobbes claiming it is outside of human ability to imagine anything not already contained in a memory or combination of memories?