diff --git a/optipdf b/optipdf
index 638cf37..81f1989 100755
--- a/optipdf
+++ b/optipdf
@@ -2,6 +2,7 @@
 # vi: et sts=4 sw=4 ts=4
 
 PRESERVE_TIMESTAMP=0
+KEEP_BACKUP_SUFFIX=.old-unoptimized
 
 TEMP_FILES=()
 cleanup() {
@@ -99,6 +100,10 @@ use_smaller() {
                 "$TEMP"
         fi &&
 
+        if [[ -n $KEEP_BACKUP_SUFFIX ]]; then
+            mv -vi -- "$FILE" "$FILE$KEEP_BACKUP_SUFFIX"
+        fi &&
+
         cp \
             --preserve=mode,ownership,timestamps \
             -- \