How can PHP be used to properly retrieve and display a PNG image stored in a MySQL database?

To properly retrieve and display a PNG image stored in a MySQL database using PHP, you need to fetch the image data from the database, set the appropriate content type header to indicate that the response is an image, and then output the image data to the browser. This can be achieved by querying the database for the image data, setting the content type header to "image/png", and echoing the image data directly to the output buffer.

<?php
// Connect to database
$connection = mysqli_connect("localhost", "username", "password", "database");

// Query database to fetch image data
$result = mysqli_query($connection, "SELECT image_data FROM images WHERE id = 1");
$row = mysqli_fetch_assoc($result);
$imageData = $row['image_data'];

// Set content type header
header("Content-type: image/png");

// Output image data
echo $imageData;