Help - Random images

[Tim Dixon]

Hi,

I have a web page which is a simple html table whish contains a picture in
one of the cells. I want this to be one of 13 random pictures (1.jpg,
2.jpg....13.jpg)

At the moment i have this line in my table.php file:

<td colspan="2" rowspan="2" valign="top" bgcolor="#999999"><img src="
<?
$random = mt_rand(1, 13);
print"images/random/$random.jpg";
?>
" width="231" height="284" border="0" alt=""></td>


.....everything works fine if I click refresh, but I want it to work
everytime I go to this page. ie. first time on page i get say 4.jpg
displayed, click refresh and say 8.jpg is displayed (working) - if i click a
link to say the homepage, then click a link from there back to 'table.php'
then the same image is displayed. It is as if it is now cached.

How do I force it to show a new pic every time?


Thanks

Tim

[php]

Use two scripts.

In the first refer to the picture with a link like this

<td colspan="2" rowspan="2" valign="top" bgcolor="#999999">
<img src="randompic.php" width="231" height="284" border="0" alt="">
</td>

then create a script named randompic.php

<?php
$dir = "./images/random";
$possible = array();
if (is_dir($dir))
{
if ($dh = opendir($dir))
{
while (($file = readdir($dh)) !== false)
if (stristr($file,".jpg")!= false) $possible[] = $file;
closedir($dh);
}
}
$x = rand(0, count($possible)-1);
$file = $possible[$x];
header("Content-Type: image/jpeg");
readfile($dir . $file);
?>

this will return a random image without causing the browser to cache it

see [url]www.offa.org[/url] for this in action

Regards

Jeff P.



"Tim Dixon" <ng@keymt.com> wrote in message
news:400e77f2$0$243$fa0fcedb@lovejoy.zen.co.uk...

> Hi,
>
> I have a web page which is a simple html table whish contains a picture in
> one of the cells. I want this to be one of 13 random pictures (1.jpg,
> 2.jpg....13.jpg)
>
> At the moment i have this line in my table.php file:
>
> <td colspan="2" rowspan="2" valign="top" bgcolor="#999999"><img src="
> <?
> $random = mt_rand(1, 13);
> print"images/random/$random.jpg";
> ?>
> " width="231" height="284" border="0" alt=""></td>
>
>
> ....everything works fine if I click refresh, but I want it to work
> everytime I go to this page. ie. first time on page i get say 4.jpg
> displayed, click refresh and say 8.jpg is displayed (working) - if i click

a

> link to say the homepage, then click a link from there back to 'table.php'
> then the same image is displayed. It is as if it is now cached.
>
> How do I force it to show a new pic every time?
>
>
> Thanks
>
> Tim
>
>

[Tom Thackrey]

On 21-Jan-2004, "Tim Dixon" <ng@keymt.com> wrote:

> I have a web page which is a simple html table whish contains a picture in
> one of the cells. I want this to be one of 13 random pictures (1.jpg,
> 2.jpg....13.jpg)
>
> At the moment i have this line in my table.php file:
>
> <td colspan="2" rowspan="2" valign="top" bgcolor="#999999"><img src="
> <?
> $random = mt_rand(1, 13);
> print"images/random/$random.jpg";
> ?>
> " width="231" height="284" border="0" alt=""></td>
>
>
> ....everything works fine if I click refresh, but I want it to work
> everytime I go to this page. ie. first time on page i get say 4.jpg
> displayed, click refresh and say 8.jpg is displayed (working) - if i click
> a
> link to say the homepage, then click a link from there back to 'table.php'
> then the same image is displayed. It is as if it is now cached.
>
> How do I force it to show a new pic every time?

If you are using PHP prior to version 4.2.0 you need to seed the mt_rand so
that it doesn't generate the same sequence each time. Add

function make_seed() {
list($usec, $sec) = explode(' ', microtime());
return (float) $sec + ((float) $usec * 100000);
}
mt_srand(make_seed());

before the line that sets $random


--
Tom Thackrey
[url]www.creative-light.com[/url]
tom (at) creative (dash) light (dot) com
do NOT send email to [email]jamesbutler@willglen.net[/email] (it's reserved for spammers)