Hi,
will krpano select the proper image based on viewer size (is that stage?) or screen resolution/size?
krpano will select the best level dynamically based on the current window/area size and on the current zoom/fov. At wide fov zooms that selection will be additionally non-linear because at wide field of views the distortion around the screen will be also non linear.
A way to control/adjust the threshold/bias of that level selecting is the
multiresthreshold setting:
On mobile devices additionally also the
memory settings are important - when the currently selected best level doesn't fit into the available memory, the krpano viewer will select automatically lower-res levels until they will fit into that memory.
Maybe have also a look at this example to get an idea about how multires will wok:
http://krpano.com/petapixel/
Best regards,
Klaus