README.md: Update according to thumbnail generation

1 files changed, 31 insertions, 2 deletions

diff --git a/README.md b/README.md
index 46cfae2..e34d401 100644
--- a/README.md
+++ b/README.md
@@ -23,6 +23,9 @@ portability, minimalism, simplicity and efficiency.
 - Uses [`libweb`](https://gitea.privatedns.org/xavi/libweb), a tiny web framework.
 - A simple JSON file as the credentials database.
 - No JavaScript.
+- Thumbnail generation can be optionally provided via a
+[separate application](thumbnail/README-md) and enabled by `slcl` via a command
+line option. Inter-process communication is achieved via a named pipe.
 
 ### TLS
 
@@ -122,16 +125,32 @@ anything users put into them.
 
 **Note:** `slcl` creates the given directory if it does not exist.
 
+[Generated thumbnails](thumbnail/README.md) are stored into another directory,
+namely `thumbnails`, which is automatically created with directory mode bits
+set to `0700`.
+
+```
+.
+├── db.json
+├── public
+├── thumbnails
+└── user
+```
+
 A more complete example:
 
 ```
 .
 ├── db.json
 ├── public
-│   └── 44e03ab1bc3b0eff1567c76619186596 -> user/alice/file.txt
+│   └── 44e03ab1bc3b0eff1567c76619186596 -> user/alice/file.jpg
+├── thumbnails
+│   ├── alice
+│   │   └── file.jpg
+│   └── john
 └── user
     ├── alice
-    │   └── file.txt
+    │   └── file.jpg
     └── john
         └── file2.txt
 ```
@@ -198,6 +217,16 @@ temporary directory to the database, which might be an expensive operation.
 Therefore, in order to avoid expensive copies, define a custom temporary
 directory that resides on the same filesystem.
 
+#### Thumbnail generation and rendering
+
+Optionally, `slcl` displays thumbnails when listing a directory, if available
+from the `thumbnails/` directory. In order to update these thumbnails when
+files are added/removed to/from the database, a separate application must be
+executed. See its [`README.md`](thumbnail/README.md) for further reference.
+
+`slcl` provides the `-F` command line option to enable the use of a named pipe
+that shall be used by the [thumbnail generation tool](thumbnail/).
+
 ## Why this project?
 
 Previously, I had been recommended Nextcloud as an alternative to proprietary