Can I have Graphics on Linux without a desktop manager?

I have a more-or-less embedded application in development that uses Linux as its OS. I get to specify the distro we use and had started with Ubunto 12.04. My applications, thankfully, are distro-independent terminal apps, and, I believe, so is most of the code from other developers. One guy though needs a graphical, web attached interface. Not sure if he is using a browser like Firefox or one that is built into Java, but it has to show graphics, still and (best answer) video.

I just can't feel that Ubuntu or even XUbuntu is my best choice for an OS. I keep wondering if one of the smaller images (Arch, DSL, etc.) or even Ubuntu in a lower runlevel, could work for me. I guess what I'm looking for is a Linux that comes up to a terminal interface (like a server OS) but can display graphics.

Is there such a beast? Perhaps someone could advise me on how to select my OS and perhaps how to better understand the graphics system on Linux - e.g. where does X stop and Gnome start. I know gnome is a desktop manager. Could I just turn that off? If I did, what would I see? How would I issue commands? Into a command prompt that show up instead of the desktop?

a Linux that comes up to a terminal interface but can display graphics. Is there such a beast?

Yes. Any GNU/Linux installation can do that.

It might not be the default configuration, but any Linux distribution with X (Xorg) can display graphics.

I know gnome is a desktop manager. Could I just turn that off?

This varies per distribution. But when you start X and log in some files in your home directory are read. These contain several things, but usually it includes which window manager you want to start after logging into X (e.g. Gnome, KDE, twm, amiwm, ...). You can replace the windows manager with your own program.

Alternatively you can test starting X and logging in without starting a windows manager by pressing F1 instead of Enter at the graphical log-in screen.

If you're trying to go lightweight, I'd recommend using Arch Linux. It comes with next to nothing out of the box, but has tons of packages, and anything you can't find is usually just a compile away in their (unsupported) AUR. It doesn't come with a Window Manager, so you get to pick what you want with as little pain as possible

For window manager, there are plenty of lightweight ones out there. Fluxbox isn't the most lightweight, but it's my favorite of the fairly lightweight ones. Just google for "lightweight xorg window managers" if Fluxbox doesn't look like a good case for you.

Although, it's also completely possible to not use a Window Manager. It's just a pain to manage :) (ie, you can edit .xinitrc to start firefox and nothing else.. it'll be a black screen with firefox in the middle of it)

X Is the base level that WM's and DE's run on and is generally required for Gnome/KDE/*Box/etc.

You have various TTY's available to you once your computer is booted (regardless of Linux distro). Generally, most Distros drop you to your login window (GDM = Gnome, Slim = Various, etc.). However, you can change to a TTY (terminal basically) or just disable the login manager. That was in /etc/inittab.

You can hit Ctrl+Alt+F1 through F7. I think F1 or F7 is the default for most (I forget which). So just do Ctrl+Alt+F3 to be safe That will do a prompt to login and then you can go from there.

I would second @Earlz on Arch. You can make it exactly what you need, it has the base linux with pacman as the manager. They have an awesome community with a fantastic Wiki.