Lightbox repeats images when swiping on mobile

blouie

Would other posters please provide whatever insights they might have about the problem described below? At least such insights could be forwarded to the SmugMug engineers:

On May 23, I noticed that, in Lightbox on a mobile device, sometimes when I swipe to advance to the next image, instead of advancing, the current image just reloads. I had been checking my site regularly, at least up to a few days before May 23, so I know the problem did not begin prior to a few days before May 23. And the problem occurs on every other SmugMug site that I have checked. SmugMug Support confirmed that it is indeed a SmugMug problem, but there is no resolution at this time.

The problem occurs in two different ways:

(1) On a mobile device, click on a link that goes directly to Lightbox, so that the first image in the Gallery displays. Then, by swiping, the next 23 images display, so that the first 24 images in the gallery have all displayed. All good. But on the next swipe, the 24th image just reloads so that it redundantly displays again. Then the problem occurs again with the 30th image, then every sixth image for the rest of the Gallery.

And when you swipe to go to the next image after a reloaded image, there is a slightly longer fraction of a second between images than usual.

For example:

https://www.markshapirophoto.com/Alone2012-2016colorgallery/n-6ZVLw9/i-DBnqHNK/A

(2) On a mobile device, click on a link that goes to the Gallery page, but don't let all the thumbnails load but instead immediately click on the first thumbnail to go to Lightbox. Then the same problem occurs as in (1).

For example:

https://www.markshapirophoto.com/Alone2012-2020bwgallery/n-9TMP86/

But the problem does not occur if first you allow all the thumbnails to load on the Gallery page then click on the first image to go to Lightbox.

On some sites other than my own, the problem starts sooner than the 24th image.

In general with SmugMug, images load - either as Thumbnails or with a Vertical layout - in batches of 48 images at a time. And the swipe problem occurs after 24 images, which is half of 48, then every 6 images, which also is a factor of 48. Maybe that’s a clue?

Maybe a change was made around May 23 to SmugMug's method for image loading? Or maybe it's a server issue?

This is not a tolerable problem. It is ridiculous and annoying for images to repeat. It ruins the crucial effect of a show of images being a continuous visual experience achieved by juxtaposition from one image to the next - the very heart of the intended effect using Lightbox.

Note: I would use Slideshow instead of Lightbox as a temporary workaround, but meanwhile Slideshow has its own unresolved issue:

https://dgrin.com/discussion/267811/slideshow-oversharpens-images#latest

blouie

The problem was fixed a few weeks ago.

It seems that they changed the number of images that load in groups to 24 images at a time, which fixed the repeating problem. (As I recall, the images used to load in groups of 48 at a time.).

This means that there is a slight delay after each 24 images before the next 24 load. But it's not too bad, and not nearly as bad as the images repeating every 7.