Just to reply to Simon, since I had the same question and found the solution : “is it possible to update thumbnail’s options with this ? Or, as I understand, it’s only for new custom image sizes ?”

In fact you can use Brad’s bt_add_image_size to create a new size, which will contain the exact same size parameters as your default media settings.

During the thumbnail creation, WordPress will automatically replace the old, middle-cropped thumbs by the new, top-cropped ones.

Example : in my Medias settings, the medium size is set to 280×280. Normally you don’t have to add a new size for this since you can set it up directly in the Dashboard.

However, Brad’s function won’t re-crop the default thumbnail, medium and large image sizes you set up in the Dashboard.

That’s why, in order to overwrite the default image sizes WordPress generates, I added the following line to my functions.php file:

bt_add_image_size('medium-thumb', 280, 280, array( 'center', 'top' ));

Since I want all my medium thumbnails to be 280×280, I simply mimic these settings in a new image size, which will simply overwrite the default 280×280 medium thumbnail generated by WordPress with Brad’s nicely cropped version.

Of course you can edit the name of this new image size (I’m not sure you should name it “medium”, “thumbnail” nor “large” since they belong to WordPress’s default namespace, pick a genuine name because you don’t want to mess with WordPress’s defaults!), the width, the height, and the crop attributes (it’s the same parameters as in CSS background-position, just like Brad explained in his post).

Hope this helps

Thanks a lot, Brad! Too bad WordPress 3.5.1 is out and your patch isn’t part of the core yet.

Many Many Thanks……

Thanks a lot for the code!

I’ve got a question however, I hope you would be able to help me out. I had 6 custom image sizes declared with add_image_size which already had all images generated for them. After finding your post I’ve changed all my declarations to bt_add_image_size for custom sizes.

I have then used AJAX Thumbnail Rebuild plugin to rebuild the images of those custom sizes with the new custom crop location. However, that didn’t seem to work.

I’ve also used the plugin that you suggested Regenerate Thumbnails However, it outputs an error after 10 successful images.

How can I make sure that the images of custom size that already had been regenerate are regenerated again using your crop position code? I would hugely appreciate your help!

Many thanks,
Dasha

I would strongly appreciate to have that extra functionality as I did implement it several times in a kind of a dirty hack in customer projects.

Kind regards!

Bastian

stumbled upon your post by accident and am very happy I found it. Helped me with a cutomers website!
I will definetly check out your post more often. keep up the good work.

Cheers, Jennifer

I see:
if ( !is_null($dest_path) and $_dest_path = realpath($dest_path) )

should that be:
if ( !is_null($dest_path) and $_dest_path == realpath($dest_path) )

Or are you purposely defining the $_dest_path?

Thanks!