diff -u b/src/Plugin/Field/FieldFormatter/PhotoswipeFieldFormatter.php b/src/Plugin/Field/FieldFormatter/PhotoswipeFieldFormatter.php
--- b/src/Plugin/Field/FieldFormatter/PhotoswipeFieldFormatter.php
+++ b/src/Plugin/Field/FieldFormatter/PhotoswipeFieldFormatter.php
@@ -127,7 +127,7 @@
         ->getFieldDefinitions($target_type, $bundle);
     }
     $fields = array_filter($fields, function (FieldDefinitionInterface $field) {
-      return $field->getType() === 'image';
+      return $field->getType() === 'image' && $field->getName() !== 'thumbnail';
     });
 
     $field_options = [];