diff --git a/README.md b/README.md
index 7d222511e3f1525222827b3f81d72ba0a0acfb45..ee7535346443517900f67ddf73ab552eb40c1772 100644
--- a/README.md
+++ b/README.md
@@ -14,7 +14,7 @@ To use the VIKUS Viewer for a custom image collection, you need to prepare metad
 
 #### [config.json](https://github.com/cpietsch/vikus-viewer-data/blob/master/vangogh/config.json)
 
-This is the configuration file that defines the project name, data URLs, columns, styles, and what is shown in the detail sidebar of your collection.
+This is the configuration file that defines the project name, data URLs, columns, styles, and what is shown in the detail sidebar of your collection. The URLs don't have to be absolute, but it can be handy if your assets are not hosted on the same server.
 
 #### [data.csv](https://github.com/cpietsch/vikus-viewer-data/blob/master/vangogh/data.csv)