.container .btn-choose-file {
    position: relative;
    overflow: hidden;
    cursor: pointer;
}
.container .btn-choose-file input {
    position: absolute;
    font-size: 50px;
    opacity: 0;
    right: 0;
    top: 0;
    cursor: pointer;
}
.container .btn-choose-file.disabled input {
    display: none;
}
#btnUpload img {
    display: none;
}
#btnUpload.uploading img {
    display: inline-block;
}