Rescaling rig with same key frame animations I want to rescale the rig which already has some animation keyframes.
But when I scale up or down, rig animation runs really weird. 
I guess it happens because of the location of the rig has changed.
Is there any possible solution that I can use the same keyframe animation with scaling up and down or do I have to make the same animations again?

Thank you.
You are applying the scale to the rig but not the mesh. This leaves them at different sizes and breaks the alignment used when attaching the rig to the mesh.

You can either use the rig to make the mesh smaller (like you had before applying the scale) or apply the same scaling to the mesh object.