include 'connect.php';

if(!empty($_FILES['file'])) {
  $allowed = array('jpg', 'gif', 'png', 'jpeg');
  $count = 0;
  foreach($_FILES['file']['name'] as $key => $name) {
    $image_name = $name;
    $tmp = explode('.', $image_name);
    $image_extn = strtolower(end($tmp)); //can only reference file
    $image_temp = $_FILES['file']['tmp_name'][$count];
    $count = $count + 1;
    if(in_array($image_extn, $allowed) === true) {
      $image_path = 'images/'.substr(md5(uniqid($name, true)),0,10).$image_extn;
      move_uploaded_file($image_temp, $image_path);
      mysql_query("INSERT INTO store VALUES ('','$image_name','$image_path')") or
        die(mysql_error());
      $lastid = mysql_insert_id();
      $image_link = mysql_query("SELECT * FROM store WHERE id = $lastid");
      $image_link = mysql_fetch_assoc($image_link);
      $image_link = $image_link['image'];
      $uploaded[] = $image_link;
    }
  }
}

function showFileSize() {
  var input, file, size, total, fileName, ext;
  var val=true;
  var imageExts = ['png', 'jpg', 'gif', 'jpeg'];
  if (typeof window.FileReader !== 'function') {
    bodyAppend("p", "The file API isn't supported on this browser yet.");
    return;
  }

  input = document.getElementById('file');
  if (!input) {
    bodyAppend("p", "Um, couldn't find the fileinput element.");
    bodyAppend("br","");
  }
  else if (!input.files) {
    bodyAppend("p", "This browser doesn't seem to support the `files` property of file inputs.");
    bodyAppend("br","");
  }
  else if (!input.files[0]) {
    bodyAppend("err","Please select a file before clicking 'Load'");
    bodyAppend("br","");
  }
  else if(input.files.length>3){
    bodyAppend("err","You can upload a maximum of three files");
    bodyAppend("br","");
  }
  else{
    for(var i=0; i<input.files.length; ++i) {
      total+=input.files[i].size;
    }
    if(total>1024*1024*2) {
      bodyAppend("err","Total uploaded file sizes must not exceed 2MB");
      bodyAppend("br","");
    }
    else {
      for(var i=0; i<input.files.length; ++i) {
        file = input.files[i];
        size = file.size;
        if(size>1024*1024*1) {
          bodyAppend("err",file.name+ " is too big, can be a maximum of 1MB");
          bodyAppend("br","");
        }
        fileName = file.name;
        ext = fileName.substring(fileName.lastIndexOf('.') + 1).toLowerCase();
        if (imageExts.indexOf(ext)  === -1) {
          bodyAppend("err",file.name+"is an incorrect file type");
          bodyAppend("br","");
          val = false;
        }
      }
      if(val==false) {
         bodyAppend("err","Allowed file types are: jpg, png, jpeg and gif");
         bodyAppend("br","");
      }
    }
  }
}


function bodyAppend(tagName, innerHTML) {
  var elm;
  elm = document.createElement(tagName);
  elm.innerHTML = innerHTML;
  document.body.appendChild(elm);
}

<form action="index.php"onsubmit="return showFileSize();" method="post" enctype="multipart/form-data">
<div>
  <input type="file" id="file" name="file[]" multiple="multiple" />
  <input type="submit" id="submit" value="Upload" onclick='showFileSize();'/>
</div>
</form>