[shotwell] Make thm a recognized extension for JPEG

[Jens Georg <jensgeorg src gnome org>]

commit 015e91e2d630619589ba80a5a45dd6d485f6cdcb
Author: Jens Georg <mail jensge org>
Date:   Sat Aug 27 15:15:37 2016 +0200

    Make thm a recognized extension for JPEG
    
    Signed-off-by: Jens Georg <mail jensge org>
    
    https://bugzilla.gnome.org/show_bug.cgi?id=759246

 src/Dialogs.vala            |    7 +++----
 src/photos/JfifSupport.vala |    2 +-
 2 files changed, 4 insertions(+), 5 deletions(-)
---
diff --git a/src/Dialogs.vala b/src/Dialogs.vala
index f01e078..10f2e43 100644
--- a/src/Dialogs.vala
+++ b/src/Dialogs.vala
@@ -1766,11 +1766,10 @@ public class AdjustDateTimeDialog : Gtk.Dialog {
         hbox.set_border_width(3);
         hbox.pack_start(image_content, true, false, 0);
         hbox.pack_start(time_content, true, false, 0);
+        hbox.valign = Gtk.Align.CENTER;
+        hbox.halign = Gtk.Align.CENTER;
 
-        Gtk.Alignment hbox_alignment = new Gtk.Alignment(0.5f, 0.5f, 0, 0);
-        hbox_alignment.add(hbox);
-
-        ((Gtk.Box) get_content_area()).pack_start(hbox_alignment, true, false, 0);
+        ((Gtk.Box) get_content_area()).pack_start(hbox, true, false, 0);
 
         notification = new Gtk.Label("");
         notification.set_line_wrap(true);
diff --git a/src/photos/JfifSupport.vala b/src/photos/JfifSupport.vala
index 3de123e..2861353 100644
--- a/src/photos/JfifSupport.vala
+++ b/src/photos/JfifSupport.vala
@@ -51,7 +51,7 @@ public class JfifFileFormatDriver : PhotoFileFormatDriver {
 
 public class JfifFileFormatProperties : PhotoFileFormatProperties {
     private static string[] KNOWN_EXTENSIONS = {
-        "jpg", "jpeg", "jpe"
+        "jpg", "jpeg", "jpe", "thm"
     };
 
     private static string[] KNOWN_MIME_TYPES = {