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Editorial Team
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Asked: 2026-06-02T07:55:47+00:00

I have these two php variables: $img1src and $img2src , (them being PHP is

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I have these two php variables: $img1src and $img2src, (them being PHP is irrelevant as you can echo a php variable anywhere) they both hold a URL of an image. I was wondering if I was able to preload these images, or cache them.

My goal is: when someone refreshes the page I want these pictures to instantly appear in a <img src >.

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1 Answer

  1. Editorial Team

    Caching an image isn’t really a job for PHP. PHP should be used to decide whether or not to display it. (There are caching things you can do with PHP, but not in the same sense.) Essentially, what you want to do is make the clients browser request the second image. Once the browser gets the image, it should automatically send an “if-modified-by” parameter in the header. Next time you load the page, the response code should be 304 and your image should load instantly. You can choose from a variety of ways to do this. Load the image with javascript after the page has loaded (to prevent additional load time) or you can just include an image tag that is hidden on the page some where.

    I also haven’t tested it, but you might be able to send an ajax request to the image directly. I’m not sure if that way would cache it or not.

    EDIT:
    This isn’t the most elegant solution, but it should get the idea across.

    JS Example:

    <?php
session_start();
if (!isset($_SESSION['graphic'])) $_SESSION['graphic'] = "http://www.tomsfreelance.com/laptop/DSC_0011.JPG";
else $_SESSION['graphic'] = "http://www.tomsfreelance.com/laptop/DSC_0012.JPG";
?>
<html>
<head>
<script>
function loadImage() {
    document.getElementById('preload').style.backgroundImage = "url(http://www.tomsfreelance.com/laptop/DSC_0012.JPG)";
}
</script>
</head>
<body onload="loadImage();">
<div id="preload" style="display: none;"></div>
<img src="<?php echo $_SESSION['graphic'];?>">
</body>
</html>
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