That's right, console image viewer: No X Windows required. Why would you want a console image viewer, you ask? Well, why wouldn't you? The Linux framebuffer has substantial graphics support, including support for different fonts and display resolutions. It's a universal hardware-independent graphical layer that you have likely already seen in action. Most Linux installers use the framebuffer on a text installation as well as to display logos at boot.
Fbida melds two programs, fbi (frame-buffer imageviewer) and ida. fbi displays console images, and ida runs on X Windows. They share common image-decoding libraries, so the developer merged the two apps to save on doing everything twice.
Fbida comes with most Linux distributions. On Fedora it comes in two packages, fbida and fbida-ida. On Debian it's fbi and ida. Ida is not needed for console use.
Using fbida is easy. Just hit Ctrl+Alt+F2 to switch to a console and run it like this:
$ fbi filename
How do you know what to use? Refer to Section 5.3 in the Framebuffer Howto. For example, to get 1024x768x16 bits, GRUB looks like this:
kernel /boot/vmlinuz-2.6.15-23-386 root=/dev/hda1 ro quiet splash vga=0x314
$ fbi *