One might say that their use of the lyric "When Dream And Day Unite" as the title of their first album could symbolize their dream of making an official album finally seeing the light of day, thus, their dream and day unite. As far as relating to the songs, the lyrics are full of "dream" ideas, such as living a dream (a fortune made in lies or gaining status), or being in a dream-like world (as seen in hell-ish future of "The Killing Hand", "Afterlife" and "The Ones Who Helped To Set The Sun").
As for the "Images And Words" lyric, I think it's just a good use of the lyric to describe what they see and write as a presentation of their creativity - their images (or music, perhaps images created by their music) and their words (their lyrics, statements and ideas). Also, it fits well after When Dream And Day Unite, as we have another album with the "And" conjunction. Also, in relation to dreams, one may often write their dreams down, in words, from the images they recall seeing in their dreams. In terms of the title's relation to the songs, it's just as simple as putting images to their words. Nothing TOO complicated here.
Then we have Awake, whose title could come from the lyrics of "Innocence Faded" and/or "The Silent Man", which could be seen as the other side of their first album's title, which deals with a dream. When one is awake, they've left their dream state, and are now conscious, and many of the songs on Awake deal with coming out of dreams or dream-states or other states of consciousness, or perhaps a form of awakening or realizations. These ideas are scattered throughout the whole album's lyrics.
In that way, I see the first three albums as a trilogy that involves dreams, their images, and an awakening from them.
Moving forward to Falling Into Infinity, one might view this as their first step into ideas concerning things being "Full Circle", as one who falls into "Infinity" would forever fall, perhaps be in a cycle. The idea itself is a paradox, as one cannot REALLY fall into "infinity", being an abstract idea, but if viewed as an endless/infinite space or time, we could note that, while falling, you cannot change your path through outside variables. Also, there are dreams where one may feel like they are endlessly falling, perhaps, into infinity, and so we have another idea/album title dealing with dreams. As for the songs on the album, there isn't TOO much of a connection, unless you consider the idea of "falling" as part of the album's lyrics' ideas, such as falling into time ("New Millennium"), falling into depression from death or related events ("Peruvian Skies", "Take Away My Pain", "Anna Lee"). I'm sure you can connect each song's lyrics to a type of falling.
Scenes From A Memory is quite an obvious connection to the lyrics of "Metropolis Part 1" being that the album is "Part 2", but the whole album's story deals with dreams, images, and awakening, as we realize that perhaps we are infinitely falling into unbreakable cycles, and that events from past lives will come full circle in the present, and will again happen in the future.
Six Degrees Of Inner Turbulence is even MORE obvious as it takes it's title from the epic track on Disc 2. But this could be viewed as another foray into the inner workings of the mind, and how turbulence in our lives affects our minds, be it with alcoholism, beliefs, reality, morals, death, or mental disabilities, all of these things affect AND change our lives and dreams.
Then we come to Train Of Thought, an idea related to "Stream Of Consciousness", a lyric from "Lines In The Sand" (from FII), and it's obvious we've come back to a title that deals with our mind and thoughts, but this album seems to be a bit more direct, and with an album title like that, perhaps with rapid, successive thoughts, rather than subconscious dreams or scattered images and memories. The songs on this album are harder, and the lyrics are more direct and less obtuse than before, so they may come from a moving "train of thought".
Now we arrive at Octavarium, the idea of things being in full circle, something that goes back to Falling Into Infinity's title, and, at least in MY opinion, this album is more like FII than the 3 before it, musically and lyrically. We get songs about things that relate to cause and effect, or how we are trapped, or even if we are free, we are still trapped in a circle of endless static living, where no matter what we do, we cannot change things or people around us. Even though this album title doesn't directly relate to dreams, the idea of things and life going in circles can relate to our cycles of dreaming and waking every day, something that we ALL do.
Systematic Chaos, as MP said (and noted above), is just a way the band writes. It can be formulaic but also very hectic. It could also relate to dreams, as even though we systematically sleep every night, our dreams may be chaotic. Our bodies do nothing but lay still, but deep in our minds, chaos may reign. Lyrically speaking, this album is full of fantasy ideas (mostly from JP), ideas that seem like dreams because they are not real (vampires, undead, dark masters, spirits, etc.), but there are also lyrics regarding mental (de)stabilization, concerning obsessive-compulsive disorder and overcoming addiction, two things that can consume a person's life if left unchecked, and thus, leaving them trapped to infinitely fall in a cycle of degradation.
Black Clouds & Silver Linings related to the songs in that, even through the darkest of moments, some good must rise out of it. This title is another use of the conjunction "and", and relates two things that are somewhat opposite (like Dreams and Days, or perhaps Images and Words).
And at the present, A Dramatic Turn Of Events seems to signify a new era, but also a change, something that seems to be key in many of the band's album titles. Usually, a turn of events signals a change in the status quo, like when dreams and days unite, or when one awakes or comes to a realization. Perhaps memories or thoughts could signal a turn of events, or events that are chaotic or covered in black clouds, which could be systematic or silver-lined in nature, despite their outwardly appearance. For me, it's the turn that changes the game/events, that reveals what things really are, bringing us to a realization or awakening, perhaps even breaking us out of an infinite fall or endless cycle.
-Marc.