也许你需要设置图像的display和position属性，你能试试吗？

<SignInGg><img src='images/google.svg' alt=''/><span>Sign in with Google</span></SignInGg>

const SignInGg = styled.a`
    font-weight: 600;
    color: rgba(0, 0, 0, 0.5);
    margin: 20px 0;
    padding: 15px 0;
    width: 35%;
    border: 2px solid rgba(0, 0, 0, 0.5);
    border-radius: 29px;
    white-space: nowrap;
    display: flex;
    flex-direction: column; // <- changed here
    align-items: center; // <- changed here
    justify-content: center; // <- changed here
    & img {
        width: 30px; 
        height: 30px; // <- changed here
        position: relative; // <- changed here
        display: inline-block; // <- changed here
    }
    &:hover {
        border: 2px solid rgba(0, 0, 0, 0.9);
        background-color: rgba(0, 0, 0, 0.1);
    }
`;