$(document).on('click', '.save', function (e) {
  var teamNameImageList = [];

  $('.teamInfo').each(function (index, value) {
    var img = this.querySelector('.teamImage').files;
    var imgFile = this.querySelector('.teamImage').files[0];
    if (imgFile != null || imgFile != undefined) {
      Promise.all(Array.prototype.map.call(img, ReadData))
        .then(function (urls) {
        teamNameImageList.push({
          Image: urls[0],
          TeamNameId: $(value).data("team-name-id")
        });

        console.log(teamNameImageList);
      });
    }
  });
});

function ReadData(file){
  return new Promise(function (resolve) {
    let reader = new FileReader();
    reader.onload = function () {
      resolve(reader.result);
    };
    reader.readAsDataURL(file);
  });
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class='teamInfo' data-team-name-id='1'>
  <input type='file' class='teamImage'/>
</div>
<div class='teamInfo' data-team-name-id='2'>
  <input type='file' class='teamImage'/>
</div>
<button class='save'>Save</button>