To him, the images in your memory are blurrable.
First, it implies what 'him' is thinking, not necessarily what's actually happening in 'your' mind.
And...it is what the speaker believes 'him' is thinking, not what he is actually thinking, and the words/symbol of meaning the speaker uses, not necessarily what accurately describes what either understands.
That said, it is completely reasonable to describe images in one's mind as blurred, since neuroscientists believe we recreate images in our mind of what actually happened, but rarely as clear as when we they first appeared. But that is not what that sentence is saying--it implies a degree of intentionality, whereas one's mind does what it does without intention. So if you are trying to imply intentionality, leave it as is, but if you are trying to describe how our minds blur images of what we remember, perhaps you say, "...the images in your memory blur over time."
As a counselor and life coach, however, I'm intrigued by the intentionality angle...how blurrable our memories become based on preconditioning and events afterwards. I do not believe the blur comes naturally alone...and when someone wants to blur a memory, conscious or otherwise, they do. So if that is what you are leading the reader to see, then keep it just the way you have it...but understand it might need more development than just one sentence, because not everyone is going to 'get' all of that meaning from one word alone.