Card scaling factor and thumbnail resolution

I find when I increase the size from the default setting, it makes the small scale art all pixelated, probably because the thumbnail generation, which I'm assuming is the resource here, still generates very low res thumbnails regardless of the scaling factor.card-scaling-factor=0.6
card-scaling-factor-enlarged=0.7
hand-scaling-factor=1.3
Is it possible to modify the thumbnail resolution somehow?
Thank you!