diff --git a/src/db.lisp b/src/db.lisp
index a6905c2..b0027ff 100644
--- a/src/db.lisp
+++ b/src/db.lisp
@@ -295,7 +295,7 @@
                            ;; one of swconf:*allowed-attachment-type*
                            " type                  TEXT NOT NULL,"
                            " url                   TEXT NOT NULL,"
-                           " \"preview-url\"       TEXT NOT NULL,"
+                           " \"preview-url\"       TEXT,"
                            " \"remote-url\"        TEXT,"
                            ;; url shortened
                            " \"text-url\"          TEXT,"
diff --git a/src/gui/client/main-window.lisp b/src/gui/client/main-window.lisp
index 496c667..6ac76eb 100644
--- a/src/gui/client/main-window.lisp
+++ b/src/gui/client/main-window.lisp
@@ -474,7 +474,9 @@
     (let ((image        (cond
                           ((string= mime-type +mime-type-jpg+)
                            (scale-jpeg main-window file-path))
-                          ((member mime-type '("image/x-tga" "image/x-targa"))
+                          ((member mime-type
+                                   '("image/x-tga" "image/x-targa")
+                                   #'string=)
                            (scale-targa main-window file-path))
                           ((string= mime-type +mime-type-png+)
                            (scale-png main-window file-path))