Subject: 29.0.50; image-dired-cmd-create-standard-thumbnail-options

From: Peter Münster <[email-masked]>
Date: Tue, 30 Nov 2021 17:24:02 +0100

Hi,

I'm a bit confused about
image-dired-cmd-create-standard-thumbnail-options:

- It seems, that it's not used with pngcrush or pngnq, so this test is
  perhaps useless:
  (unless (or image-dired-cmd-pngcrush-program
              image-dired-cmd-pngnq-program) ...
- If gm is used, then the "convert" command should be added.

The attached patch works for me, but probably I'm missing something...

-- 
           Peter
diff --git a/lisp/image-dired.el b/lisp/image-dired.el
index 47a44a4a60..159f6a3b97 100644
--- a/lisp/image-dired.el
+++ b/lisp/image-dired.el
@@ -302,19 +302,17 @@ image-dired-cmd-optipng-options
   :link '(url-link "man:optipng(1)"))
 
 (defcustom image-dired-cmd-create-standard-thumbnail-options
-  (append '("-size" "%wx%h" "%f[0]")
-          (unless (or image-dired-cmd-pngcrush-program
-                      image-dired-cmd-pngnq-program)
-            (list
-             "-set" "Thumb::MTime" "%m"
-             "-set" "Thumb::URI" "file://%f"
-             "-set" "Description" "Thumbnail of file://%f"
-             "-set" "Software" (emacs-version)))
-          '("-thumbnail" "%wx%h>" "png:%t"))
+  (let ((opts (list "-size" "%wx%h" "%f[0]"
+              "-set" "Thumb::MTime" "%m"
+              "-set" "Thumb::URI" "file://%f"
+              "-set" "Description" "Thumbnail of file://%f"
+              "-set" "Software" (emacs-version)
+              "-thumbnail" "%wx%h>" "png:%t")))
+      (if (executable-find "gm") (cons "convert" opts) opts))
   "Options for creating thumbnails according to the Thumbnail Managing Standard.
 Available format specifiers are the same as in
 `image-dired-cmd-create-thumbnail-options', with %m for file modification time."
-  :version "26.1"
+  :version "29.1"
   :type '(repeat (string :tag "Argument")))
 
 (defcustom image-dired-cmd-rotate-original-program