<div class="seeImg">
    <img :src="url"/>
</div>

    .seeImg {
        width: 100%;
        height: 100%;
        background: url("../assets/images/background.png") no-repeat center;
        background-size: 100% 100%;
        position: relative;
    }

    .seeImg img {
        width: auto;
        height: auto;
        max-height: 100%;
        max-width: 100%;
        position: absolute;
        top: 0;
        bottom: 0;
        left: 0;
        right: 0;
        margin: auto;
    }