diff --git a/CHANGELOG.md b/CHANGELOG.md
index a115537..ee867fb 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## Unreleased
+### Added
+* `sxiv-arguments` to hold argument list
 ### Fixed
 * Slow startup/freezing on large directories
 
diff --git a/README.md b/README.md
index 4843fe7..402cf00 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,7 @@ With prefix argument, or when only provided directories, run recursively.
 Run it from a text file containing one file name per line to open the listed files.
 
 ## TODO
-1. Create user-customizable variable to hold default arguments
+1. [x] Create user-customizable variable to hold default arguments
 2. Start sxiv on the file at point (using `-n ...`)
 3. Let user specify paths to be excluded.
 4. Mark files in subdirectories if run recursively (by inserting the subdirectory into the current buffer)
diff --git a/sxiv.el b/sxiv.el
index d116d5c..a9b64f6 100644
--- a/sxiv.el
+++ b/sxiv.el
@@ -12,6 +12,15 @@
 
 ;;; Code:
 
+(defgroup sxiv nil
+  "Run the Simple X Image Viewer."
+  :group 'external)
+
+(defcustom sxiv-arguments '("-a" "-f" "-o")
+  "Arguments to be passed to the sxiv process.
+It must contain \"-o\" for marking in Dired buffers to function."
+  :type '(repeat string))
+
 (defvar sxiv--directory nil
   "Directory `sxiv' was called from.
 Used by `sxiv-filter' to know where to mark files.")
@@ -82,7 +91,10 @@ the files listed."
          (proc    (make-process :name "sxiv"
                                 :buffer "sxiv"
                                 :command
-                                (apply #'list "sxiv" "-afo" recurse "--" paths)
+                                (append '("sxiv")
+                                        sxiv-arguments
+                                        `(,recurse "--")
+                                        paths)
                                 :connection-type 'pipe
                                 :stderr "sxiv-errors")))
     (setq sxiv--directory default-directory)