homepage image oversized on ipad

I have been struggling with the Ipad view of my 2013-site (which looks fine in computer browsers), and can’t find a way to solve this particular problem:

The homepage image (inserted in a special homepage template) is way oversized when viewed on Ipad, in such a way that the image looks normal but the rest (header, menu, footer) looks way smaller. Is there an easy way to solve this?

The link is:
https://saskialensink.nl/