Thumbnail sizing

This is an album-set gallery:
As you can see, the thumbnail image has been blown-upped way larger than the already large thumbnail window.
The image used for this was sized at 3373 x 7051pixels and published to the page via Lightroom’s Publisher module. Upon inspection, we see that the image once uploaded is now 122 x 256pixels.
How does Lightroom Publisher reduce the size of the image to that extent?
In Backlight/AlbumSettings/Image Rendition, we have a thumbnail set at 70 x 140pixels.
The thumbnail style is set at CLASSIC with an aspect ratio of x=1 y=2.

What do I fail to grasp: is how to set the thumbnail frame size and how to fit the image inside of it?

All this was rather straightforward in Backlight 4 but since the upgrade to 5, I am fumbling around trying to control and set the thumbnail sizes on this page.

In your album set template you’re using the Iconic layout. The ratio is 3:1, making them a horizontal panoramic. In the Iconic layout, the image covers the area.

Remember, the thumbnail images used in the album set come from the album thumbnails within the set. They have nothing to do with the large image rendition size.
You have your album thumbnails set to a 1:2 ratio, tall verticals. These don’t match the aspect ratio you’ve set in the album set template.

So in the Iconic album set, a 3:1 slice is taken out of the album thumbnails and used in the set.

If you want to use the Iconic layout in your album set, you either need to use thumbnails in the albums that are the same ratio and sized large enough so that they don’t need to be stretched, or you need to create custom thumbnails at the same ratio and sufficiently sized.

In your case, in the album set you could change the thumbnail ratio to 1:2. And the thumbnails created by the album need to be large enough to fill the space in the album set without degrading

The sizing for the thumbnails is insufficient for both the album and the album set. The thumbnails in the album look fuzzy.

Iconic thumbnail sizing has not changed from BL 4 to BL 5. It’s been this way since at least the CE days.

It’s not. Looking at one of the albums, the large images are set to be published at 600x940 and that’s what’s been uploaded. And the large images look just fine. The thumbnails are sized at 70x140. This thumbnail size is what’s being fit into the larger area you’ve created in the albums by the gallery max-width, the thumbnail aspect ratio, and the number of columns.
For example, on an average desktop monitor, with the browser taking up the entire screen, I see six columns of thumbnails in the album. Because the gallery max-width is set so large, these six columns are about 250px wide each and those 70px wide thumbnails are being stretched to fill the space.

Control the thumbnail display size in the albums by changing the album max-width as well as the number of columns

I set the album set template as Iconic at a ratio of 1:1 and that thumbnail size suits me fine.
And, of course, the thumbnails in the album come out at 1:1 also. But the images are still too big and are cut off top and bottom.
If I set the album-set thumbnail ratio to 2:1, I get very tall thumbnails (it looks like 4:1) and the image is stretched.
Finally, I set the ratio at 3:2, I get reasonable thumbnails but the image is still so big it’s cropped.
So then I set the gallery max-width at 1440. I’ve got 6 columns when the browser is 1920px wide, the maximum screen size. The layout looks good but the images are still too big.
That would suggest that the thumbnails are larger than the image, thus stretching it to fill. Correct?

Lastly, as a “learning tool”, I set the album at CLASSIC with a yellow background and an orange border. It’s a very graphic way to see the different sizes of the images!

I may have to rethink all of the thumbnail business.

That’s what happens with the iconic layout if the ratio set in the album set does not match the ratio of the album thumbnails.

Yes, the space allocated for the thumbnails is larger than the thumbnails themselves.

If you like the Iconic layout for the album set, then I might make sense to take the time to create custom thumbnails to fit.

I’ve come to a decision: Albums-set will have thumbnails at 7:13 aspect ratio, max-thumbnail width at 100 (the minimum), and gallery width at 1440. Looks ok even if not quite satisfactory.
If I do come around to creating custom thumbnails, is it possible for this image to not show in the gallery?
Using the export feature in Lightroom is deceiving: If a 1000px image is exported “as is”, it still comes out smaller than the original size. Is something wrong with my Lightroom? Conversely, if I upload fairly large images (4000px wide) they still show up as very small thumbnails!
So, I’ll live with this setup for a while, until I get my head around this thumbnail-sizing business.

Tylenol, anyone?


Doubtful. Might just be a misunderstanding of the Export settings. In the Export dialog, under Image Sizing, there is a checkbox that allows you to resize using several choices of options. If you don’t want to resize but just want to export at the original size, don’t check that box.

I think you’re misunderstanding how the thumbnails are sized. The setting is in the album template under Image Renditions > Thumbnails
That will create thumbnails at the size indicated in the template. How they actually display in an album set using the Iconic layout is up to the settings in the album set. If the display area is larger than the actual size of the thumbnail, you get low quality images in the album set.

And why would you be uploading 4000px images unless you’re creating large renditions for download?

That 4000pixel example was just for the sake of argument.
But, I was reminded that I did this once before, a few years back: creating a folder named _custom thumbnails and checking the hide from album set and hide from search boxes.
Now, all I have to do is created a series of images sized specifically for the thumbnail boxes.

You could do it using the old method of the custom_thumbnails album. Or just upload directly using the tools in Backlight

Being not too familiar with the direct-to-Backlight method, I opted for the old custom_thumbnails method and it works fine. I had to “normalize” a few of the images to fit the format but otherwise, it works fine.

Thanks for all the help, Rod.

The new method is a lot easier. Try it out, Matt has a video on it in the docs page I linked to above

Right on! Just tried it and it’s much faster and easier, as long as the image meets the format requirements. In that case, a little LR work does the trick.