How to create a thumbnail on the fly

adam291086 · April 8, 2008

Anybody know of a tutorial on how to generate thumbnails on the fly?

discomatt · April 8, 2008

http://www.google.ca/search?q=php+thumbnails+on+the+fly

That wasn't difficult

Just as a warning, generating thumbnails on the fly can be taxing on a server. If you're with a shared host, they may not appreciate generation on the fly if you start seeing some decent traffic.

craygo · April 8, 2008

http://www.phpfreaks.com/forums/index.php/topic,191541.0.html

adam291086 · April 8, 2008

i am using the code by craygo, thanks very much. Although i am getting no images, just a box with a red cross. Heres the code

<?php


$folder = glob("images/*.jpg"); 

foreach($folder AS $file)
{




//large image
$large = $file;
//thumbnail

?>
	<td>
	<img src="imageresize.php?maxsize=xxx&source=<?php echo $file ?>" border=0 />
	</td>
	<td>

<?php
    }
?>

when i look at the html source code of the images i get

<td>
	<img src="imageresize.php?maxsize=xxx&source=images/Picture 043.jpg" border=0 />
	</td>
	<td>

craygo · April 8, 2008

have to change the maxsize(xxxx) to the max size you want

<img src="imageresize.php?maxsize=200&source=<?php echo $file ?>" border=0 />

Ray

adam291086 · April 8, 2008

Still the same any idea

craygo · April 8, 2008

i imagine you put the function in it's own file and called it imageresize.php?? And that file is in the same directory as the script your running??

Ray

adam291086 · April 8, 2008

yep. I copied the code exactly as its printed in your thread, and called it imageresize.php

craygo · April 8, 2008

I copied your exact code, I happen to have an images folder also , and it works fine.

thumbs.php

<?php
$folder = glob("images/*.jpg");

foreach($folder AS $file)
{
//large image
$large = $file;
//thumbnail
?>
	<td>
	<img src="imageresize.php?maxsize=200&source=<?php echo $file; ?>" border=0 />
	</td>
	<td>

<?php
    }
?>

and imageresize.php

<?php
/**********************************
*  Will resize an image to a      *
*  max width or height and keep   *
*  aspect ratio Name this file    *
*  anything you like.             *
*  I will use imageresize.php     *
**********************************/

header('Content-type: image/jpeg');
function resampleimage($maxsize, $sourcefile, $imgcomp=0){
// SET THE IMAGE COMPRESSION
$g_imgcomp=100-$imgcomp;
  // CHECK TO SEE IF THE IMAGE EXISTS FIRST
  if(file_exists($sourcefile)){
  // FIRST WE GET THE CURRENT IMAGE SIZE
  $g_is=getimagesize($sourcefile);
    /********* CALCULATE THE WIDTH AND THE HEIGHT ***************/
    // CHECK TO SEE IF THE WIDTH AND HEIGHT ARE ALREADY SMALLER THAN THE MAX SIZE
    if($g_is[0] <= $maxsize && $g_is[1] <= $maxsize){
    // LEAVE WIDTH AND HEIGHT ALONE IF IMAGE IS SMALLER THAN MAXSIZE
    $new_width=$g_is[0];
    $new_height=$g_is[1];
    } else {
    // GET VALUE TO CALCULATE WIDTH AND HEIGHT
    $w_adjust = ($maxsize / $g_is[0]);
    $h_adjust = ($maxsize / $g_is[1]);
      // CHECK TO WHICH DIMENSION REQUIRES THE SMALLER ADJUSTMENT
      if($w_adjust <= $h_adjust){
      // CALCULATE WIDTH AND HEIGHT IF THE WIDTH VALUE IS SMALLER
      $new_width=($g_is[0]*$w_adjust);
      $new_height=($g_is[1]*$w_adjust);
      } else {
      // CALCULATE WIDTH AND HEIGHT IF THE HEIGHT VALUE IS SMALLER
      $new_width=($g_is[0]*$h_adjust);
      $new_height=($g_is[1]*$h_adjust);
      }
    }
  //SEARCHES IMAGE NAME STRING TO SELECT EXTENSION (EVERYTHING AFTER THE LAST "." )
$image_type = strrchr($sourcefile, ".");

//SWITCHES THE IMAGE CREATE FUNCTION BASED ON FILE EXTENSION
switch($image_type) {
	case '.jpg':
		$img_src = imagecreatefromjpeg($sourcefile);
		break;
	case '.jpeg':
		$img_src = imagecreatefromjpeg($sourcefile);
		break;
	case '.png':
		$img_src = imagecreatefrompng($sourcefile);
		break;
	case '.gif':
		$img_src = imagecreatefromgif($sourcefile);
		break;
	default:
		echo("Error Invalid Image Type");
		die;
		break;
}
  // CREATE THE TRUE COLOR IMAGE WITH NE WIDTH AND HEIGHT
  $img_dst=imagecreatetruecolor($new_width,$new_height);
  // RESAMPLE THE IMAGE TO NEW WIDTH AND HEIGHT
  imagecopyresampled($img_dst, $img_src, 0, 0, 0, 0, $new_width, $new_height, $g_is[0], $g_is[1]);
  // OUTPUT THE IMAGE AS A JPEG.
  // THIS CAN BE CHANGED IF YOU WANT TRANSPARENCY OR PREFER ANOTHER FORMAT. MAKE SURE YOU CHANGE HEADER ABOVE.
  imagejpeg($img_dst);
  // DESTROY THE NEW IMAGE
  imagedestroy($img_dst);
  return true;
  } else {
  return false;
  }
}
// NOW CALL THE IMAGE FROM ANY OTHER PAGE WITH <img src="imageresize.php?maxsize=xxx&source=path/to/image/file" border=0 /> xxx=a value for the max size
resampleimage($_GET['maxsize'], $_GET['source']);
?>

They cannot be in the same file. If it is not working I am not sure why. I copied and pasted your code verbatim and it works fine.

Ray

adam291086 · April 8, 2008

they are definitely in the same file.

I have a folder called gallery. In there there is the two files along with another folder storing the images

dennismonsewicz · April 8, 2008

Try this thread:

http://www.phpfreaks.com/forums/index.php/topic,191420.msg859481.html#msg859481

adam291086 · April 9, 2008

still having problems here is the current situation.

I have a folder called gallery and in here there are the imageresizer script and a template.php that calls on the imagersizer script. The images are coming from a folder called imager which is in the gallery folder.

Is this correct

writer · April 9, 2008

It could be that the script can't handle the space in your image title (perhaps "Picture_043.jpg" would work). Maybe you need to echo it out in ASCII?

<img src="imageresize.php?maxsize=xxx&source=images/Picture 043.jpg" border=0 />

laffin · April 9, 2008

<img src="imageresize.php?maxsize=xxx&source=images/Picture 043.jpg" border=0 />/[code]
will not work, use urlencode, or remove/replace spaces in the name

[/code]

adam291086 · April 10, 2008

i have removed the spaces and nothing has changed

craygo · April 10, 2008

List each file and the code in each file so we can get to the bottom of this.

Also list your directory structure.

Ray

adam291086 · April 10, 2008

ok,

i have a folder in the root directory of my server called gallery.

In here i have;

image.php which is the script you gave me
template.php which calls on your script to generate the images
a folder call images which contains all my images

these are all the scripts

image.php

<?php
error_reporting(E_ALL);
/**********************************
*  Will resize an image to a      *
*  max width or height and keep   *
*  aspect ratio Name this file    *
*  anything you like.             *
*  I will use imageresize.php     *
**********************************/

header('Content-type: image/jpeg');
function resampleimage($maxsize, $sourcefile, $imgcomp=0){
// SET THE IMAGE COMPRESSION
$g_imgcomp=100-$imgcomp;
  // CHECK TO SEE IF THE IMAGE EXISTS FIRST
  if(file_exists($sourcefile)){
  // FIRST WE GET THE CURRENT IMAGE SIZE
  $g_is=getimagesize($sourcefile);
    /********* CALCULATE THE WIDTH AND THE HEIGHT ***************/
    // CHECK TO SEE IF THE WIDTH AND HEIGHT ARE ALREADY SMALLER THAN THE MAX SIZE
    if($g_is[0] <= $maxsize && $g_is[1] <= $maxsize){
    // LEAVE WIDTH AND HEIGHT ALONE IF IMAGE IS SMALLER THAN MAXSIZE
    $new_width=$g_is[0];
    $new_height=$g_is[1];
    } else {
    // GET VALUE TO CALCULATE WIDTH AND HEIGHT
    $w_adjust = ($maxsize / $g_is[0]);
    $h_adjust = ($maxsize / $g_is[1]);
      // CHECK TO WHICH DIMENSION REQUIRES THE SMALLER ADJUSTMENT
      if($w_adjust <= $h_adjust){
      // CALCULATE WIDTH AND HEIGHT IF THE WIDTH VALUE IS SMALLER
      $new_width=($g_is[0]*$w_adjust);
      $new_height=($g_is[1]*$w_adjust);
      } else {
      // CALCULATE WIDTH AND HEIGHT IF THE HEIGHT VALUE IS SMALLER
      $new_width=($g_is[0]*$h_adjust);
      $new_height=($g_is[1]*$h_adjust);
      }
    }
  //SEARCHES IMAGE NAME STRING TO SELECT EXTENSION (EVERYTHING AFTER THE LAST "." )
$image_type = strrchr($sourcefile, ".");

//SWITCHES THE IMAGE CREATE FUNCTION BASED ON FILE EXTENSION
switch($image_type) {
	case '.jpg':
		$img_src = imagecreatefromjpeg($sourcefile);
		break;
	case '.jpeg':
		$img_src = imagecreatefromjpeg($sourcefile);
		break;
	case '.png':
		$img_src = imagecreatefrompng($sourcefile);
		break;
	case '.gif':
		$img_src = imagecreatefromgif($sourcefile);
		break;
	default:
		echo("Error Invalid Image Type");
		die;
		break;
}
  // CREATE THE TRUE COLOR IMAGE WITH NE WIDTH AND HEIGHT
  $img_dst=imagecreatetruecolor($new_width,$new_height);
  // RESAMPLE THE IMAGE TO NEW WIDTH AND HEIGHT
  imagecopyresampled($img_dst, $img_src, 0, 0, 0, 0, $new_width, $new_height, $g_is[0], $g_is[1]);
  // OUTPUT THE IMAGE AS A JPEG.
  // THIS CAN BE CHANGED IF YOU WANT TRANSPARENCY OR PREFER ANOTHER FORMAT. MAKE SURE YOU CHANGE HEADER ABOVE.
  imagejpeg($img_dst);
  // DESTROY THE NEW IMAGE
  imagedestroy($img_dst);
  return true;
  } else {
  return false;
  }
}
// NOW CALL THE IMAGE FROM ANY OTHER PAGE WITH <img src="imageresize.php?maxsize=xxx&source=path/to/image/file" border=0 /> xxx=a value for the max size
resampleimage($_GET['maxsize'], $_GET['source']);
?>

template.php

<?php
error_reporting(E_ALL);
$folder = glob("images/*.jpg");

foreach($folder AS $file)
{
//large image
$large = $file;
//thumbnail
?>
	<td>
	<img src="image.php?maxsize=200&source=<?php echo $file ?>" border=0 />
	</td>
	<td>

<?php
    }
?>

craygo · April 10, 2008

the only way this will not work is if GD in not activated on your server. Do you know if it is??

Ray

adam291086 · April 10, 2008

no i don't know if it's active or not. It seems it's not

craygo · April 10, 2008

is the web server yours?? Do you have access to the php.ini file??

To find out if it is on just make a temp page and inside put in

<?php
phpinfo();
?>

This will output php setting about a third of the way down the page there should be a section called gd. if it's enabled then something unknown is going on, but if it is not there or sayd disabled then you have to activate it. And you can only do that in the php.ini file.

Ray

adam291086 · April 10, 2008

according to the phpinfo its all enabled. What the f..k is going on

craygo · April 10, 2008

is this a public or private site??

adam291086 · April 10, 2008

not sure what you mean by that, the hosting company is 1 and 1.

craygo · April 10, 2008

ok can I get to the site from here. can you give me a link

Ray

adam291086 · April 10, 2008

yeah its adamplowman.co.uk/template.php

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How to create a thumbnail on the fly

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