Leave width of image rendering of infoboxes up to the template

However make sure it doesn't exceed the size of the viewport
* Disclaimer: This will break rendering of image on phones that do
not support max-width and have resolutions smaller than the image - but
this should be left to the template to take care of

Bug: 49440
Change-Id: Iec09df6c8a513287d24f29dba1700c58a155a5ae
Merge "Leave width of image rendering of infoboxes up to the template"