Thumbnails won't create with 8bpp JPEG

[cannonball_]

When you upload a 8bpp JPEG image with media library, thumbnails won't create and only fullsize image avaible to use.

[DD32]

8bpp greyscale image which can trigger problem.

[DD32]

Cause: file_is_displayable_image()

​http://trac.wordpress.org/browser/trunk/wp-admin/includes/image.php#L272

	elseif ( $info['channels'] > 0 && $info['channels'] != 3 ) {
		// some web browsers can't display cmyk or grayscale jpegs

I'm assuming that this Greyscale 8bit image issue is the same as the poster is having?

I'm not sure on the actual issue here, Some browsers cannot display the image yes, But its still being displayed regardless.

[pishmishy]

Works for me in FF3 in OS X. I can view the original image just fine in this configuration, and I can see the thumbnail too. Closing as worksforme, but please provide further information on your browser and platform if you wish.

[DD32]

Problem persists.

Env: Windows XP SP2 + Apache2.2 + PHP 5.2.4 + GD 2.0.34

Browser/OS makes no difference in this case, As its entirely server-side related.

Steps to reproduce:

1. Upload attached file 001.jpg
2. File will be crunched as normal, uploaded, and will appear fine
3. Thumbnail is not created, The thumbnail on the media page will be the fullsize 001.jpg rescaled via the img height= and width= attributes
4. Insert the image into a post via the thumbnail selection, The code inserted will be the fullsize image:
   

   <a href="http://localhost/wordpress-trunk-clean/wp-content/uploads/2008/06/001.jpg">
   <img class="alignnone size-thumbnail wp-image-7" title="001" src="http://localhost/wordpress-trunk-clean/wp-content/uploads/2008/06/001.jpg" alt="" />
   </a>
   

If you were to insert a gallery with that image in it, The thumbnail would not exist, and as such, the original image will be shown in the gallery, At its original resolution (Which can be 1200pixels wide with some that i've come accross)

Some older software has issues with mono jpegs & cmyk jpegs, and would probably produce a blank image. In this case though, Its not an interesting.

Related:

• ​http://wordpress.org/support/topic/174062

Apply attached patch, Follow through with the above steps, insert a thumbnail, and recieve the correct code:

<a href="http://localhost/wordpress-trunk-clean/wp-content/uploads/2008/06/001.jpg">
<img src="http://localhost/wordpress-trunk-clean/wp-content/uploads/2008/06/001-150x150.jpg" alt="" title="001" width="150" height="150" class="alignnone size-thumbnail wp-image-9" />
</a>

[arminbw]

Replying to DD32:

Some older software has issues with mono jpegs & cmyk jpegs, and would probably
produce a blank image. In this case though, Its not an interesting.

CMYK jpeg images show up in modern browsers without any indication.
However, after uploading no thumbnails are generated by WP.
No error message informs the user about that.

Afterwards functions like "wp_get_attachment_thumb_url" will return the full-size image giving no hints about the source of all these the troubles. (There can be other sources: ​http://trac.wordpress.org/ticket/7278)

A "no thumbnail available" image instead of the full-size image would be helpful.
A "CMYK not supported. No thumbnails have been created" message after the upload would be helpful.
Actual, converting the image to RGB before/while creating the thumbnail would be great.

[arminbw]

a CMYK image

[DD32]

Some older software has issues with mono jpegs & cmyk jpegs, and would probably produce a blank image. In this case though, Its not an interesting.

Wow.. "Its not an interesting." What? :)

What i probably meant to say, Was that Allthough older software has issues with these types of files, Modern software is not going to have any problem with it, The chances of running into a browser or server with an old gd version is probably less likely than users who can handle it and want to use it?

[azaozz]

(In [9727]) Fix thumbnails creation for 8bpp and CMYK images, props DD32, fixes #7039 fixes #8231