Rename image.fwhm by image.fwhm_gauss
It would be better to rename the image.fwhm() with image.fwhm_gauss() because the algorithm assume that the function is Gaussian. For other function, eg Moffat it does not give the right result.
It would be better to rename the image.fwhm() with image.fwhm_gauss() because the algorithm assume that the function is Gaussian. For other function, eg Moffat it does not give the right result.