The standing image is in the pose called "Buddha Dispelling Fear". Buddha's mere presence inspired
such awe as to result in a shocking fright for those encountering him for the first time. The palm
up gesture is intended to becalm such a frightened soul.
The seated image is of the variety known
as "Buddha Subduing Mara". Mara, simply put, is Evil. Mara often attempted to disrupt Buddha's meditations.
Sometimes the Naga would shelter and protect Buddha from these distractions
but other times Buddha would simply reach down for the earth with his right hand and thereby become
'connected' with Earth and thus be able to put Mara out of his mind.