CarrierWave :: RMagick resize_to_fit后丢失PNG图像质量

I'm using CarrierWave::RMagick to create thumbnail versions of images for a Rails app, and I've noticed loss of quality when the images are downsized. This is understandable to a certain extent, as we have less pixels in a downsized image and therefore less quality, but I would expect better quality. I show you an example: to create thumbn