For some upcoming blog posts on videograms, I will start by explaining the difference between a motiongram and a videogram. Both are temporal (image) representations of video content (as explained here), and are produced almost in the same way. The difference is that videograms start with the regular video image, and motiongrams start with a motion image.
So for a video of my hand like this:
we will get this horizontal videogram:
and this horizontal motiongram:
As you see, they both reflect the video content. The main difference is that the videogram preserves the original background colours, while the motiongram only reflects what changes between the frames (i.e. the motion).