Php pdf image preview code - php

Question

I try to generate php code in order to preview an image from a pdf file. Here is my code. There is an error but i cannot understand where it is. I would appreciate any help. Thank you.
<?php
//Get Menu Bar
include('navigate.php');
?>
<table cellspacing="4" width=100%><tr><?php if(!$vol){ ?><td bgcolor="eeeeee" width="50%" valign="top">
<h3 style=" text-shadow:#003">Latest News:</h3>
<?php
$latest=mysql_query("select * from articles ORDER BY id DESC LIMIT 1", $link);
while ($article = mysql_fetch_array($latest)) {
$thevolume= $article['volume'];
$title= $article['title'];
$author= $article['author_main'];
$abstract= $article['abstract'];
$pdf= $article['pdf'];
$im = new imagick('pdf');
$im->setImageFormat('jpg');
?>
<a href="<?php echo $pdf; ?> "PDF: ?php echo "$title - $author"; ?>
<img src="<?php echo $im; ?> " WIDTH="98%" border="1" title="<?php echo "$title - $author"; ?> " caption="Click here to open PDF" />
</a>

Answer 1

You must to pass as parameter a path to PDF file, not only the string 'pdf': http://php.net/imagick.construct
If $article['pdf'] contains it you must to use:
$im = new imagick(realpath($pdf) . '[0]');
$im still being a resource that contains a object instance of imagick, and not the image or pdf document itself, so you must to do this to inline image in HTML (if you want to use JPEG, I would use PNG):
<img src="data:image/jpg;base64,<?php
echo base64_encode($im->getImageBlob());
?> " WIDTH="98%" border="1" title="<?php
echo htmlspecialchars("$title - $author");
?> " caption="Click here to open PDF" />
Note the usage of htmlspecialchars ( http://php.net/htmlspecialchars ) to output strings to navigator and getImageBlob ( http://php.net/imagick.getimageblob ) to get image data (if available) and finally I will encode it in base64 to inline it in HTML document.
If you want to link to a cached version of image you must to save it in a temporary file or create another PHP script to generate the image from PDF file.
Best regards,
Edit 1: How to create a JPEG thumbnail, from PHP manual:
You should read this: http://php.net/imagick.setimageformat#89210
This example will help you:
// convert to JPEG
$im->setImageColorspace(255);
$im->setCompression(Imagick::COMPRESSION_JPEG);
$im->setCompressionQuality(60);
$im->setImageFormat('jpeg');
Probably you will wish to reduce image size:
$im->resizeImage(290, 375, imagick::FILTER_LANCZOS, 1);
And remember to import the page number (beginning with 0, not 1) adding '[0]' to file name as edited.
Good luck!