Blurry thumbnails

The thumbnails on this page but not the thumbnails here ?

All the images are of similar size.

Your images are only 64px-squares. You should check the settings for your thumbnail renditions, then re-upload files to generate new images for the gallery.

That’s strange, some of these images are 3868 x 5415 pixels in the dng format. When the act of publishing, via Lightroom is working, does it reduce the size of these images and is there a setting for this?
I did a test: the image used for the cover thumbnail for the album SCRAPBOOK is GBC230405-2588 and it’s a jpeg 1691 x 2114 pixels uploaded directly in Backlight. The original thumbnail I was using was in 3382 x 4227 pixels dng format uploaded with Lightroom’s Publisher. And there is no apparent change in image sharpness. And I set the thumbnail size to 500 pixels…

Clearly, something escapes me.

Yes, it’s in the Image Rendition portion of the album template.

If you’ve made a change to 500px and you’re not seeing the change upon republishing the album, check your Lightroom Publisher settings and make sure that “Push metadata without updating existing photos” is not checked.

Examining the thumbnails, the smallest one is 571 x 799 pixels, jpeg format. The largest is 3868 x 5415 pixels, DNG format. All have been uploaded with LR’s Publisher. The Lightroom Publisher settings are 400 x 300 pixels and “Push metadata without updating existing photos” is not checked. Yet, it’s the larger thumbnails that looked blurred.

UPDATE: I republished everything at the settings listed above and the thumbnails now look better.
Thank you Matthew and Rod.

Much better. FYI, if you open the inspector in Chrome, you can mouse over the src address, and see a pop up like this. It shows you the “Rendered size” (the size the image appears on the page), and the “Intrinsic size” (the actual size of the image file). This is, as you might imagine, very useful information when debugging images.