关于图片上传改名和压缩的问题

第二次用到同样文件名的图片，进行上传时提示文件已存在，路径也保存不了数据库，文件名也无法存入数据库，导致不显示。，请教大神在哪里加代码处理这个问题？

第二个问题，在哪里加代码压缩图片文件大小

<?phpif (count($_FILES)) {    $retFiles = uploadFile("file");    if ($retFiles['status'] == 1) {        echo $retFiles['message'];    } else if ($retFiles['status'] == 0) {        echo "Upload: " . $retFiles["name"] . "<br />";        echo "Type: " .  $retFiles["type"] . "<br />";        echo "Size: " . ($retFiles["size"] / 1024) . " Kb<br />";        echo "Temp file: " . $retFiles["temp"] . "<br />";        echo "Stored in: " . "../upload/" . $retFiles["name"];    }}
function uploadFile($fileName){ $files = $_FILES[$fileName];    if (!in_array($files["type"], array("image/gif","image/jpeg","image/pjpeg","image/jpeg", "image/png"))) {        return array("status" => 1, "message" => "Uploaded image format is not correct");    }        if ($files["error"] > 0) {        return array("status" => 1, "message" => "upload error");    }    if (file_exists("../upload/" . $files["name"])) {        return array("status" => 1, "message" => $files["name"]." already exiss");    }        move_uploaded_file($_FILES['file']['tmp_name'], '../upload/'.iconv("UTF-8", "gbk",$_FILES['file']['name']));    return array("status" => 0, "name" => $files["name"], "type" => $files["type"], "size" => $files['size']/1024, "temp" => $files["tmp_name"]); }