Get image width and height with PHP

I was working on my World War II photo gallery recently. The gallery’s HTML code, particularly the main content section, looks something like the following.

<div id="content">
	<div class="main_column">
		<img decoding="async" src="images/helloWorld.jpg">
		<!--
		The photograph and other "main content" goes here.
		The width of this column is 600px.
		-->
	</div>

	<div class="extra_column">
		<!--
		This is the vertical side bar.
		If the width of the photo in the main section is more
		than 600px, it will overlap this div.
		-->
	</div>
</div>

Because my vertical navigation bar is on the right side of the page, if a photograph is larger than a particular width, it overlaps the vertical bar. I decided to remove the vertical bar if the photo is too large; let us assume that if the image width is larger than 580 pixels, it is too large. To apply the logic, I used the getimagesize() function. A quick example on this function is below.

list($imageWidth, $imageHeight, $imageType, $imageAttr) = getimagesize($imgName);
echo("The width of the image is ".$imageWidth." pixels.");
// Sample output: "The width of the image is 600 pixels."

I used the following PHP code to make my page work the way I want to based on width of the image.

<div id="content">
	<?php
	$imgName = "helloWorld.jpg";

	list($imageWidth, $imageHeight, $imageType, $imageAttr) = getimagesize($imgName);

	if ($imageWidth <= 580) { ?>
		<div class="main_column">
	<?php } ?>

	<img decoding="async" src="images/helloWorld.jpg">
	<!--
	The photograph and other "main content" goes here.
	-->

	<? if ($imageWidth <= 580) { ?>
		</div>
		<div class="extra_column">
		<!--
		This is the vertical side bar.
		Only show this if image width
		is 580 pixels or smaller.
		-->
		</div>
	<?php } ?>
</div>

Beyond width, the getimagesize() function in PHP also outputs other properties; the output is an array containing four elements. As you may have noticed, in my above example, I captured the following properties.

• 0 $imageWidth : Width of the image in pixels; integer.
• 1 $imageHeight : Height of the image in pixels; integer.
• 2 $imageType : Type of the image; integer. Possible values are as follows:
  

  Value	Description
  1	GIF
  2	JPG
  3	PNG
  4	SWF
  5	PSD
  6	BMP
  7	TIFF (Intel)
  8	TIFF (Motorola)
  9	JPC
  10	JP2
  11	JPX
  12	JB2
  13	SWC
  14	IFF
  15	WBMP
  16	XBM

• 3 $imageAttr : HTML-formatted attributes; string. Example: ‘height=”600″ width=”400″‘