According to
https://www.flickr.com/services/api/explore/flickr.photos.search
if I set a page number greater than the number of pages, then it still returns results. Hence this now never finishes (it did when I last ran my backup a few months ago):

   if (count($photos['photo']) == 0) {

Fix appears to be (I'm not a php coder by a long stretch):

diff --git a/Offlickr2.php b/Offlickr2.php
index 6a97958..2d00451 100755
--- a/Offlickr2.php
+++ b/Offlickr2.php
@@ -396,8 +396,13 @@ class Offlickr2 {
if (count($photos['photo']) == 0) {
break;
}

•  if ($page > $photos['pages']) {
  

•    printf ("debug: past the end of pages? $page > %s\n", $photos['pages']);
  

•    break;
  

•  }
  

  foreach ($photos['photo'] as $photo) {
  array_push($this->photo_list, $photo['id']);

•    printf ("debug: %s %d\n", $photo['id'], $page);
  

  }
  $retrieved = count($this->photo_list);
  $this->dialog->info(2, "Total so far: " . $retrieved . " photo(s)");

P.S. why do I need this in my local version to stave off php warnings?
diff --git a/LocalStorage.php b/LocalStorage.php
index 0eb009c..4e8b221 100644
--- a/LocalStorage.php
+++ b/LocalStorage.php
@@ -18,6 +18,8 @@ abstract class LocalItem {
}

function setup_temporary_dir() {

• $path="/tmp";
• $prefix="offlickr2.";
  // FIXME: Not atomic
  $tempname = tempnam($path,$prefix);
  if (!$tempname) {
  @@ -329,4 +331,4 @@ class LocalStorage {

}

-?>
\ No newline at end of file
+?>