Currently, Nimbus will look at the image file extension to determine if the image is compressed or not. That works well when we assume that images will always be named with the proper suffix. But it could be that the actual image filename is out of the user's control, as when the image is stored and managed in an image repository. Then there is not guarantee
that this image repository will return an image url ending with the .gz suffix.
It would be nice if there was a feature to tell Nimbus to use system file tests to determine if the image is compressed or not. (Such as with the 'file' unix command). That would make the image compression feature independent of image name suffixes.