picture not responsive

hi,

I used joomla 3.2.3 , plugin t3 2.1.2 and template v.2.1.2.

theme dark with and layout home 2

i want at position Home-1 vrom layout a picture with used width 100% for desktop it is working but for tablet or mobile the width from picture is not responsive the picture is much bigger than the layout see picture

how can i solve that

regards
Gerhard