Multiple Image Upload PHP form with one input

extract($_POST);
$error=array();
$extension=array("jpeg","jpg","png","gif");
foreach($_FILES["files"]["tmp_name"] as $key=>$tmp_name) {
    $file_name=$_FILES["files"]["name"][$key];
    $file_tmp=$_FILES["files"]["tmp_name"][$key];
    $ext=pathinfo($file_name,PATHINFO_EXTENSION);

    if(in_array($ext,$extension)) {
        if(!file_exists("photo_gallery/".$txtGalleryName."/".$file_name)) {
            move_uploaded_file($file_tmp=$_FILES["files"]["tmp_name"][$key],"photo_gallery/".$txtGalleryName."/".$file_name);
        }
        else {
            $filename=basename($file_name,$ext);
            $newFileName=$filename.time().".".$ext;
            move_uploaded_file($file_tmp=$_FILES["files"]["tmp_name"][$key],"photo_gallery/".$txtGalleryName."/".$newFileName);
        }
    }
    else {
        array_push($error,"$file_name, ");
    }
}

and you must check your HTML code

<form action="create_photo_gallery.php" method="post" enctype="multipart/form-data">
    <table width="100%">
        <tr>
            <td>Select Photo (one or multiple):</td>
            <td><input type="file" name="files[]" multiple/></td>
        </tr>
        <tr>
            <td colspan="2" align="center">Note: Supported image format: .jpeg, .jpg, .png, .gif</td>
        </tr>
        <tr>
            <td colspan="2" align="center"><input type="submit" value="Create Gallery" id="selectedButton"/></td>
        </tr>
    </table>
</form>

Nice link on:

PHP Single File Uploading with vary basic explanation.

PHP file uploading with the Validation

PHP Multiple Files Upload With Validation Click here to download source code

PHP/jQuery Multiple Files Upload With The ProgressBar And Validation (Click here to download source code)

How To Upload Files In PHP And Store In MySql Database (Click here to download source code)