Don't take my word as gospel, but I'm pretty sure 
that the other type of eyecatch cel is pretty 
much a cel that is used for a much longer time 
than normal without any panning involved.  The 
example that comes to mind is Violinist of 
Hameln, which, towards the end of the series, 
seems to be at least half of it be UN-animated, 
just one picture on the screen during narration 
etc.  They usually have motion lines drawn in, 
and are a bit more artistic than norm, since, 
well, there's no moving going about.

I have no idea if they're bigger than normal 
though... but it wouldn't seem so if it were for 
a series, would it?  Making it bigger would 
require more mobility and zooming/etc of the 
machines, which would just cost more.  But that's 
just my common sense, not an informed opinion.