Here is a sample form for single file upload.
<form action=”file_upload.php” enctype=”multipart/form-data” method=”post”>
Provide Image: <input type=”file” name=”image_file” />
<input type=”submit” title=”Upload” />
</form>

And the PHP code to upload file
< ?
// file_upload.php
// Check if the file uploaded successfully
if(is_uploaded_file($_FILES["image_file"]['tmp_name']))
{
$image_type = "";
//for security check the image type
switch($_FILES["image_file"]["type"])
{
case "image/pjpeg":
case "image/jpeg":
case "image/gif":
$image_type = $_FILES["image_file"]["type"];
default:
echo "Invalid image type";
exit;
break;
}

$image = chunk_split(base64_encode(file_get_contents($_FILES["image_file"]['tmp_name'])));
// here you can save the image and image type in DB
// You will output image type in header() when displaying image
}
?>

For multiple files upload, visit the above link or ask again.