Can't reduce the size of background image in Drag and Drop


I'm using Quiz (Question Set). In Drag and Drop, I use an image 400*400px and this is the size of the zone activity. But whe n I launch the quiz, the image is show 950*950px. 

The code show that :

<div class="h5p-inner" role="application" aria-labelledby="dq-intro-4" style="background-image: url(&quot;; height: 950px; width: 950px; font-size: 50.6667px;"><div class="h5p-draggable ui-draggable h5p-advanced-text" tabindex="0" role="button" style="left: 69.3333%; top: 26.6667%; width: 4.95078em; height: 1.70078em; touch-action: none; border-color: rgb(198, 198, 198); box-shadow: rgba(0, 0, 0, 0.2) 0px 0px 10.1333px 0px; background-color: rgb(221, 221, 221); background-image: none;"><span class="h5p-hidden-read">Eléments déplaçables 1 de 3.</span><p>bac</p>

How can I change the size showed to students ?

Thank you very much.