dieudonne Try add this in css field area :
.gk-nsp-art .gk-nsp-image:hover,article figure.featured-image:hover img,.gk-nsp-links .gk-image-link:hover img,article figure.featured-image:hover img,article figure.featured-image:hover img {
-webkit-transform: none !important;
-moz-transform: none !important;
-ms-transform: none !important;
-o-transform: none !important;
transform: none !important;
}
Kindly ensure to clear your browser cache if changes dont reflect