add gif comparing alignment

Author: smathermather

source/tutorials.rst

@@ -846,6 +846,12 @@ Workflow for multi-temporal datasets:
     [INFO]    auto_boundary: True
 
 
+.. figure:: images/align_pc.gif
+   :alt: Animated gif comparing two separately processed, but aligned digital surface models.
+   :align: center
+
+Animated gif comparing two separately processed, but aligned digital surface models.
+
 
 Using Singularity
 =================