woocommerce/packages/js/components/src/image-gallery/image-gallery-item.scss

.woocommerce-image-gallery__item {
    height: 146px;
    width: 146px;
	position: relative;

	&.is-toolbar-visible{
		img {
			border: 2px solid #007cba;
		}
	}

    img {
		border: 1px solid $gray-200;
		border-radius: 3px;
		box-sizing: border-box;
        max-width: 100%;
    }

    .woocommerce-pill {
        background: var(--wp-admin-theme-color);
        border: 0;
        color: $white;
        padding-top: 2px;
        padding-bottom: 2px;
        position: absolute;
        top: 10px;
        left: 10px;
    }

	.components-toolbar-group {
		flex-wrap: inherit;
		border-right: 1px solid #ccc;

		svg {
			width: 24px;
		}
	}

}