To scale and center an image based on wrapper size

scaled-centered-image.scss

.field-items {
                        position: absolute;
                        margin: auto;
                        top: 0;
                        left: 0;
                        right: 0;
                        bottom: 0;
                        width: 60%;
                        height: 60%;
                        .field-item {
                            img {
                                position: absolute;
                                margin: auto;
                                top: 0;
                                left: 0;
                                right: 0;
                                bottom: 0;
                                max-width: 100%;
                                max-height: 100%;
                                width: auto;
                                height: auto;
                            }
                        }
                    }