Image thumbnails not generating

Have you tried deactivating all of your plugins and switching to the default Twenty Fourteen theme? See if that fixes it.

This is on a previously working website. Additionally, I have verified that thumbnails are generated correctly with the same theme, plugins and WordPress version on a local VM version of the website.

I think there is something more than a plugin conflict going on here. If I knew more about how WordPress generates the thumbnails I might be able to debug this further.

I’m having an issue with a WP 3.9.2 install running…

Did this happen as soon as you installed WordPress 3.9.2?

I don’t think so. Like I’ve said previously, I have a separate VM (virtual machine) install with the same WP 3.9.2, theme and plugins as my live website and it does not have this issue.

This points to something wrong with my live website, but what??? I don’t know what part of the WordPress code actually generates the thumbnails and what might cause it to fail.

My suspicion is that this might have something to do with the GD library. I was hoping that someone with more knowledge than me could verify that this is the case or that the issue is likely with something else.

On the off chance that it might help, I have re-installed WP 3.9.2 on this site. Now the thumbnail files are generated when I upload images. However, the [gallery] short code still refuses to use them. The HTML generated uses scaled full-size images (sucks for page size). Previous posts with galleries use the thumbnails as they should.

Any other ideas on what might be going on???

OK, I’ve taken a look at the HTML and there are some possible clues to what is going on here but I’m not sure what they are pointing to, hopefully someone will know right off.

All galleries are created via the [gallery] short code and specify “Link to” as the “Attachment Page” in all cases.

Old posts generate HTML that looks like this:

<div id='gallery-1' class='gallery galleryid-510 gallery-columns-5 gallery-size-thumbnail'><dl class='gallery-item'>
			<dt class='gallery-icon landscape'>
				<a href='https://cardinalacresphotography.com/brickyard-vintage-racing-invitational/june-06-2014-at-10-10-42/'><img width="188" height="188" src="https://cardinalacresphotography.com/wp-content/uploads/2014/06/June-06-2014-at-10-10-42-188x188.jpg" class="attachment-thumbnail" alt="Porsche 911 RS" /></a>
			</dt></dl><dl class='gallery-item'>
			<dt class='gallery-icon landscape'>
				<a href='https://cardinalacresphotography.com/brickyard-vintage-racing-invitational/june-06-2014-at-10-21-13/'><img width="188" height="188" src="https://cardinalacresphotography.com/wp-content/uploads/2014/06/June-06-2014-at-10-21-13-188x188.jpg" class="attachment-thumbnail" alt="Jaguar XK150" /></a>
			</dt></dl><dl class='gallery-item'>
			<dt class='gallery-icon landscape'>
				<a href='https://cardinalacresphotography.com/brickyard-vintage-racing-invitational/june-06-2014-at-10-26-34/'><img width="188" height="188" src="https://cardinalacresphotography.com/wp-content/uploads/2014/06/June-06-2014-at-10-26-34-188x188.jpg" class="attachment-thumbnail" alt="Well Used Tools" /></a>
			</dt></dl>
...
			<br style='clear: both' />
		</div>

While new posts generate HTML that looks like this:

<div id='gallery-6' class='gallery galleryid-693 gallery-columns-5 gallery-size-thumbnail'><dl class='gallery-item'>
			<dt class='gallery-icon landscape'>
				<a href='https://cardinalacresphotography.com/?attachment_id=663'><img width="188" height="125" src="https://cardinalacresphotography.com/wp-content/uploads/2014/08/August-02-2014-at-10-20-16.jpg" class="attachment-thumbnail" alt="August 02, 2014 at 10-20-16" /></a>
			</dt></dl><dl class='gallery-item'>
			<dt class='gallery-icon landscape'>
				<a href='https://cardinalacresphotography.com/?attachment_id=664'><img width="188" height="125" src="https://cardinalacresphotography.com/wp-content/uploads/2014/08/August-02-2014-at-10-21-18.jpg" class="attachment-thumbnail" alt="August 02, 2014 at 10-21-18" /></a>
			</dt></dl><dl class='gallery-item'>
			<dt class='gallery-icon portrait'>
				<a href='https://cardinalacresphotography.com/?attachment_id=667'><img width="125" height="188" src="https://cardinalacresphotography.com/wp-content/uploads/2014/08/August-02-2014-at-10-27-46.jpg" class="attachment-thumbnail" alt="August 02, 2014 at 10-27-46" /></a>
			</dt></dl>
...
			<br style='clear: both' />
		</div>

Note the differences:

• the old posts use the 188×188 thumbnails for the gallery grid while the new posts use the full resolution images scaled to 188×125 (sucks for page size)
• the old posts exclusively use the ‘gallery-icon-landscape’ class for dt tags while the new posts use both ‘gallery-icon-landscape’ and ‘gallery-icon-portrait’ depending on the image
• the old posts link directly to the full-resolution image file while the new posts link to the attachment page (yes, I double-checked that the old gallery settings were also set “Link To” to “Attachment Page”

Argh! Pulling my hair out trying to figure out what is causing this…

Anyone know where the [gallery] short code pulls it’s HTML from? Is that specified as part of the theme? If so, where would I find the appropriate theme file (I suppose this is theme dependent, though, so might be impossible to answer; I’m using the Autofocus Pro theme if that helps).

Any help with this greatly appreciated…

OK, I think what is happening is that the theme-specific HTML for galleries that is supposed to override the default WordPress gallery style isn’t being loaded (looks like this happens in /wp-includes/media.php).

Unfortunately, my PHP knowledge is little to none at this point and I can’t figure out where/how a theme overrides the default WordPress gallery styling. Can anyone point me in the right direction???

If it helps any, the theme I’m using is AutoFocus Pro.

Thanks! Starting to feel like I’m having a conversation with myself…

Just wait for WordPress 4.0. It is planned to be released today.

Correction, it is most likely going to be released September 3.

4.0 makes no difference. Old galleries display correctly, but new galleries do not.

Still think this has something to do with overriding the default WP gallery style. If anyone could help me debug this it would be MUCH appreciated!

I have another website that is showing some similar symptoms to this one: thumbnails that were previously generated are no longer generated when new images are added and image/gallery display is not working correctly. This is with the Reactive theme (https://themeforest.net/item/reactive/3262385).

Matthew, I take it from your above comment that there is some kind of known issue with WP 3.9.2 and images/galleries. Can you provide some details or point me to a bug report?

Is it possible to downgrade WP to a version that works correctly with images? If so, can you provide details.

Thanks!

OK, after some more work I have discovered that the original issue I had reported with the AutoFocus theme is somehow related to PHP compatibility. Using v5.2.x works while v5.3.x doesn’t (at least with my hosting provider). I’m hoping that the AutoFocus developer can help determine exactly what is going on here (I’ve submitted a support request on the developer’s website to this end).

Now if I could just figure out what is going on with my site running the Reactive theme…

I’m having this same issue but in the opposite direction.

My gallery was pulling images id=”gallery-6″ now on my local environment it’s setting id=”gallery-2″.

I’m about to give up on local development. It just always seems like something gets mucked up. I’m also no wiz and it’s likely entirely my fault.

Rhymes: your issue doesn’t sound like it is the same or similar to my issue.

As I posted above, the issue with one of my sites was resolved by downgrading to PHP 5.2. With the other site, the issue was with the theme failing to generate the image thumbnails as I recall. An update to that theme (Reactive) solved the issue.

You may want to contact your theme developer for assistance…