profile__picture 사진 크기 조정

<header class="header">
        <nav class="header__content">
            <div class="header__buttons">
                <a href="index.html" class="header__home">
                    <img src="assets/icons/logo.svg" alt="logo">
                </a>
            </div>
            <div class="header__search">
                <img src="assets/icons/search.svg" alt="search">
                <input type="text" placeholder="Search...">
            </div>
            <div class="header__buttons">
                <a href="#none">
                    <img src="assets/icons/home.svg" alt="home">
                </a>
                <a href="#none">
                    <img src="assets/icons/shop.svg" alt="shop">
                </a>
                <a href="#none">
                    <img src="assets/icons/messenger.svg" alt="messenger">
                </a>
                <div class="profile__picture">
                    <img src="assets/images/avatar.png" alt="user picture">
                </div>
            </div>
        </nav>
    </header>

.header {
    width: 100%;
    height: 44px;
    background-color: #FFFFFF;
    display: flex;
    justify-content: center;
    position: fixed;
    top: 0;
    left: 0;
    z-index: 2;
    border-bottom: 1px solid #DBDBDB;
}

.header__content {
    width: 100%;
    max-width: 975px;
    padding: 0 14px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.header__logo {
    margin-top: 5px;
}

.header__search {
    width: 216px;
    height: 28px;
    display: none;
    align-items: center;
    position: relative;
}

@media (min-width: 768px) {
    .header__search {
        display: flex;
    }
}

.header__search img {
    width: 12px;
    height: 12px;
    position: absolute;
    top: 8px;
    left: 8px;
}

.header__search input {
    width: 100%;
    height: 100%;
    background-color: #FAFAFA;
    padding: 4px 10px 4px 28px;
    border: 1px solid #DBDBDB;
    border-radius: 4px;
    outline: none;
    font-size: 12px;
    /* 폰트 굵기 */
    font-weight: 300;
    color: #999999;
    text-overflow: hidden;
    white-space: nowrap;
}

.header__search input:focus {
    color: #262626;
}

.header__buttons {
    display: flex;
    align-items: center;
    gap: 16px;
}

.profile__picture img{
    width: 24px;
    border-radius: 50%;
}

css의 .profile__picture부분에서 저는 강의처럼 말고 뒤에 img를 넣어야지만 사진 크기가 조정되는데 img를 안붙혀도 되는 이유가 궁금합니다!