Edit image gallery for mobile only

You can add this to Design > Custom CSS

/* Gallery strips 2 columns mobile */
@media (max-width: 576px) {
    .gallery-strips .gallery-strips-wrapper {
        columns: 2;
        column-gap: 0;
        height: auto!important;
        display: block!important;
        padding: 0 5px;
    }
    .gallery-strips-item-wrapper {
        height: auto!important;
    }
    .gallery-strips-item {
        position: relative!important;
        transform: none!important;
        width: 100%!important;
        display: block;
        padding: 5px!important;
        box-sizing: border-box;
    }

    .gallery-strips .gallery-strips-item img {
        height: 100%!important;
      	width: 100%!important;
    }
}