diff --git a/README.md b/README.md
index c98bc24..8313c7c 100644
--- a/README.md
+++ b/README.md
@@ -50,7 +50,7 @@ Option             | Use
 ------------------ | -------------------------------------------------------------------
 `Port`             | the port number jaf will listen on
 `LinkPrefix`       | a string that will be prepended to the file name generated by jaf
-`FileDir`          | path to the directory jaf will save uploaded files in
+`FileDir`          | path to the directory jaf will save uploaded files in. if using docker-compose needs to be the same as the target mount point (the right side)
 `LinkLength`       | the number of characters the generated file name is allowed to have
 `ScrubExif`        | whether to remove EXIF tags from uploaded JPEG and PNG images (`true` or `false`)
 `ExifAllowedIds`   | a space-separated list of EXIF tag IDs that should be preserved through EXIF scrubbing (only relevant if `ScrubExif` is `true`)