Changing image resolution for mipmapping

Hi there,

I'm working on an app showing user uploaded maps (bitmaps). These maps can be of any resolution and often they are very large. Now down-scaling these images they become ugly and crunched, so I need to use mipmapping (Working in WebGL).

I know mipmapping only works with "powered by two" resolutions, but is there any way I can resample my odd-sized maps, to fit into a "pb2" resolutioned baseTexture, and still know the original specs. Or how would you work around it?

Thanks