Jason--

There are many reasons I don't quite recommend creating the thumbnails
on the fly with ImageMagick:

1) I've heard many say that storing/retrieving images from MySQL
databases isn't the greatest idea, because you end up with -huge-
tables, which leads to long query times.
2) Resizing a JPEG on the fly is a very CPU intensive task
3) Calling the shell, then calling the ImageMagick program is more and
more overhead.

If you insist on storing the images in the database, then you're best
off storing the thumbnails in there too.  If you insist on creating
thumbnails on the fly, then I suggest you install PHP 4.0.6 with GD
2.0.1 and use ImageCopyResampled() or ImageCopyResized() to do it--
it'll save you from spawning a shell and running an external program.

I had to create a Real Estate site, where house listings could be posted
with photos to accompany them... When a photo was uploaded (HTTP
upload), the script would use ImageCreateTrueColor() to create two new
images, then I called ImageCopyResampled() to resize the image to two
different sizes-- one thumbnail for search results, then a larger one
for listing details.

I stored these images in a directory in the format:

/images/1_thumb.jpg
/images/1_full.jpg

And so on... The number (1 in this case) corresponded with the
auto_increment ID of the MySQL record for the item.

When the listing is deleted, PHP deletes the associated images
automatically (if they exist).

Good luck!


-----Original Message-----
From: Jason Bell [mailto:[EMAIL PROTECTED]] 
Sent: Thursday, July 12, 2001 7:27 PM
To: [EMAIL PROTECTED]
Subject: [PHP] Thumbnail Generation from DB Stored Images.


Hello! I have images stored in a MySQL Database. I can retrieve the
images and display them without a problem, but I'd really like to be
able to create thumbnails. The code that I've written just doesn't seem
to work. Preferably, I'd like to pull the image from the database, and
create the thumbnail for display, without ever writing an image to the
disk. If this is not possible, I'd like to know alternate methods. I'm
using imagemagick's convert utility to create the thumbs. Here is my
code:

getpic.php:

<?php
if($id) {
    @MYSQL_CONNECT("localhost","username","mypassword");
    @mysql_select_db("daelic");
    $query = "select image,type from images where id=$id";
    $result = @MYSQL_QUERY($query);
    $data = @MYSQL_RESULT($result,0,"image");
    $type = @MYSQL_RESULT($result,0,"type");
    Header( "Content-type: $type");
    echo $data;
};
?>

tgen.php:

<?php
if ($id) {
          $src = getpic.php?id=$id;
          $thumb = passthru("convert -geometry 40% $src jpeg:-");
          print $thumb;
         };
?>


I know that getpic.php works.  I can use it in like this:   echo "<IMG
SRC='getpic.php?id=$id'>"; and it will output the fullsize graphic in
place. I'm trying to get to a point where I can use tgen.php in the same
mannor. I can use the same convert command if I use an actual file, like
pics/mypic.jpg and it works, so the command is good.....

any help at all would be very appreciated,

Jason Bell


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