image resizing (thumbnails)

timandkitty

I'm having trouble using imagecopyresized() to create some thumbnails for my gallery site.

Here is the code I'm using:

<?php imagecopyresized('thumbnail.png','bigpic.png',0,0,0,0,60,38,600,380) ; ?>
<img src=thumbnail.png>

and i'm getting this error:

Warning: Supplied argument is not a valid Image resource

Is there something I'm forgetting to do?

As a side note, in case it's important, I'm able successfully to use these functions:

imageCreateFrompng()
imageSX()
imageCopyMerge()
imagepng()

...and I'm running PHP 4.0.6

THANKS!!!

nnichols

The function takes image identifiers not image files -

<? 
$new_w=100; 
$new_h=100; 

header("Content-type: image/gif"); 

$dst_img=ImageCreate($new_w,$new_h); 

$src_img=ImageCreateFromPNG("bigpic.gif"); 

ImageCopyResized($dst_img,$src_img,0,0,0,0,$new_w,$new_h,ImageSX($src_img),ImageSY($src_img)); 

ImageGif($dst_img); 

?>

I have attached a php file containing a function to generate thumbnails. You simply pass in the image you want to create a thumnail of, the name of the thumbnail you are to create and the dimensions. Have a play

Hope this helps 😉

timandkitty

It works great.

Now the reason it wasn't working before is because they needed to be references... like $thumbnail instead of "thumbnail.png"?

Am I understanding correctly?

Thanks again!

nnichols

Now the reason it wasn't working before is because they needed to be references... like $thumbnail instead of "thumbnail.png"?

Am I understanding correctly?

Yes. BUT that doesn't mean set "$var = file.png" and then pass that to the function. You must create an image that php can work with by using the "ImageCreateFrom___()". Then php can manipulate the image.

Hope that makes sense. There is a reasonable explanation of this in the PHP manual.

Nick 😉

VoiD

btw, If you can get access to it, you should try ImageMagick.
It works wonders (for me at least).

Resizing images is just 1 line of code.
Thumbnailer? 1 line of code.
Adding watermarks (with alpha transparancy!) 1 line of code.

Check out their site: http://www.imagemagick.com/

Quality of resizing is WAY better than the gd.