How can PHP developers ensure that PHPlot images are displayed correctly in a web page?

To ensure that PHPlot images are displayed correctly in a web page, PHP developers should make sure that the image is generated and outputted properly with the correct content type header. This can be achieved by using the `header()` function in PHP to set the content type to `image/png` or `image/jpeg` before outputting the image data.

<?php
require_once 'phplot.php';

// Create a PHPlot object and set up the data and plot type

// Generate the image
$plot->DrawGraph();

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

// Output the image
$plot->PrintImage();