check file size and info

file_check.js

#preview img{height:100px;}
<input id="browse" type="file"  multiple />
<div id="preview"></div>

window.URL    = window.URL || window.webkitURL;
var elBrowse  = document.getElementById("browse"),
    elPreview = document.getElementById("preview"),
    useBlob   = false && window.URL; // `true` to use Blob instead of Data-URL

function readImage (file) {
  var reader = new FileReader();
  reader.addEventListener("load", function () {
    var image  = new Image();
    image.addEventListener("load", function () {
      var imageInfo = file.name    +' '+
                      image.width  +'×'+
                      image.height +' '+
                      file.type    +' '+
                      Math.round(file.size/1024) +'KB';
      elPreview.appendChild( this );
      elPreview.insertAdjacentHTML("beforeend", imageInfo +'<br>');
    });
    image.src = useBlob ? window.URL.createObjectURL(file) : reader.result;
    if (useBlob) {
      window.URL.revokeObjectURL(file); // Free memory
    }
  });
  reader.readAsDataURL(file);  
}

elBrowse.addEventListener("change", function() {
  var files  = this.files;
  var errors = "";
  if (!files) {
    errors += "File upload not supported by your browser.";
  }
  if (files && files[0]) {
    for(var i=0; i<files.length; i++) {
      var file = files[i];
      if ( (/\.(png|jpeg|jpg|gif)$/i).test(file.name) ) {
        readImage( file ); 
      } else {
        errors += file.name +" Unsupported Image extension\n";  
      }
    }
  }
  if (errors) {
    alert(errors); 
  }
});