.wp-block-image.is-style-tablet-image {
    display: none;
}
.wp-block-image.is-style-desktop-image {
    display: none;
}

@media only screen and (min-width: 600px) {
    .wp-block-image.is-style-mobile-image {
        display: none;
    }
    .wp-block-image.is-style-tablet-image {
        display: block;
    }
}

@media only screen and (min-width: 990px) {
    .wp-block-image.is-style-tablet-image {
        display: none;
    }
    .wp-block-image.is-style-desktop-image {
        display: block;
    }
}