How to show a random picture in a web page? - php

Question

My website has an image in a certain place and when a user reloads the page he should see a different image on the same place. I have 30 images and I want to change them randomly on every reload. How do I do that?

Answer 1

Make an array with the "picture information" (filename or path) you have, like
$pictures = array("pony.jpg", "cat.png", "dog.gif");
and randomly call an element of that array via
echo '<img src="'.$pictures[array_rand($pictures)].'" />';
Looks weird, but works.

Answer 2

The actual act of selecting a random image is going to require a random number. There are a couple of methods that can help with this:
rand() is used to generate a random number.
array_rand() is used to select a random element's index from an array.
You can think of the second function as a shortcut for using the first if you're specifically dealing with an array. So, for example, if you have an array of image paths from which to select the one you want to display, you can select a random one like this:
$randomImagePath = $imagePaths[array_rand($imagePaths)];
If you're storing/retrieving the images in some other way, which you didn't specify, then you may not be able to use array_rand() as easily. But, ultimately, you need to generate a random number. So some use of rand() would work for this.

Answer 3

If you store the information in your database, you can also SELECT a random image:
MySQL:
SELECT column FROM table
ORDER BY RAND()
LIMIT 1
PgSQL:
SELECT column FROM table
ORDER BY RANDOM()
LIMIT 1
Best,
Philipp

Answer 4

An easy way to create random images on popup is this method below.
(Note: You have to rename the images to "1.png", "2.png", etc.)
<?php
//This generates a random number between 1 & 30 (30 is the
//amount of images you have)
$random = rand(1,30);
//Generate image tag (feel free to change src path)
$image = <<<HERE
<img src="{$random}.png" alt="{$random}" />
HERE;
?>
* Content Here *
<!-- Print image tag -->
<?php print $image; ?>
This method is simple and I use this every time when I need a random image.
Hope this helps! ;)

Answer 5

I've recently written this which loads a different background on every pageload. Just replace the constant with the path to your images.
What it does is loop through your imagedirectory and randomly picks a file from it. This way you don't need to keep track of your images in an array or db or whatever. Just upload images to your imagedirectory and they will get picked (randomly).
Call like:
$oImg = new Backgrounds ;
echo $oImg -> successBg() ;
<?php
class Backgrounds
{
public function __construct()
{
}
public function succesBg()
{
$aImages = $this->_imageArrays( \constants\IMAGESTRUE, "images/true/") ;
if(count($aImages)>1)
{
$iImage = (int) array_rand( $aImages, 1 ) ;
return $aImages[$iImage] ;
}
else
{
throw new Exception("Image array " . $aImages . " is empty");
}
}
private function _imageArrays( $sDir='', $sImgpath='' )
{
if ($handle = #opendir($sDir))
{
$aReturn = (array) array() ;
while (false !== ($entry = readdir($handle)))
{
if(file_exists($sDir . $entry) && $entry!="." && $entry !="..")
{
$aReturn[] = $sImgpath . $entry ;
}
}
return $aReturn ;
}
else
{
throw new Exception("Could not open directory" . $sDir . "'" );
}
}
}
?>