Newest pictures of set not shown

Creating the block from scratch with the same parameters in the sandbox also shows the wrong last taken photos. This excludes it is a caching issue.

Enabling the Devel module and uncommenting line 911 in flick.inc shows us on block save:
$type=photoset $delta=7 $id=72157647138841941 $sort=date-taken-desc $filter= $page=1 $per_page=72 $tags= $vocab_isset=0 $total=75 $lat= $lon= $radius=

$per_page=72 shows that our querying of the Flickr API is too limited (we have 75 photos in the set). We made the API request quicker by limiting the number of photos to return. For recent sorted photos this is 4 x the displayed number to provide a sufficient distinction between recently uploaded and recently taken. Your problem would temporarily taken care of by setting the number of photos to display to 21 (4x21=84 > 75). When the number in the set reaches 85, you have the same problem again.

Our problem lies in the fact that flickr.photosets.getPhotos returns a list with the oldest photos first. The attached patch solves the issue for sets up to 500 photos. That seems acceptable to not compromise performance too much, but it remains a limitation.

TODO: Add a note in the documentation about it.

Thanks for reporting. Providing the used parameters to replicate the issue was fundamental.

More performant and without the limitation of 500.

Added a debug part and a fallback in case $per_page is not set or 0, avoiding an empty album for this reason.

I have tested your patch on my website and now I am indeed able to display the 18 most recent pictures..

I guess it can be set to RTBC then.

That's a nice use case you linked to. I always like to see the module in action.

Thanks for testing.