While reading the code I noticed the suffix options in the Pageimage class.
It seems some settings are added as suffix but not all. So my workaround for now is:
$url1 = $image->size(100, 100)->url;
$url2 = $image->size(100, 100, array('upscale' => false, 'cropping' => false, 'suffix' => array('noupscsale', 'nocrop')))->url;
Resulting in:
image.100x100.jpg
image.100x100-noupscale-nocrop.jpg