Left Image: C/2011 W3 Lovejoy in SOHO C3 (17 December UT). Right Image: C/2011 W3 Lovejoy in STEREO beacon (low resolution) images in H1A (17 December, far right). Click to embiggen. Image credit NASA/SOHO and NASA/SECCHI. (earlier images here and here).
Images show brightness of the comet and the development of the ion tail.
The comet has been telescopically imaged in daylight a few times now, see image from Jakub Cerny here and from Jan here.
SOHO animation 17-12-11
STEREO H1A beacon image animation 17-12-11