diff --git a/README.md b/README.md
index 4d2fba4..0830b30 100644
--- a/README.md
+++ b/README.md
@@ -1 +1,9 @@
-# pfnano-image-build
+# PFNano conatainer image
+
+This container image had been built to investigate whether an increased timeout value solves the problem observed with the file access from eospublic.
+
+It has the PFNano code installed from https://github.com/cms-opendata-analyses/PFNanoProducerTool and compiled. See [Dockerfile](Dockerfile).
+
+The container is available from `ghcr.io/katilp/pfnano-image-build:main`
+
+The build is done in [the GitHub workflow](.github/workflows/docker-publish.yml). As it requires more space than is available in a normal GitHub runner, some unused libraries are removed from the runner in the workflow. This does not affect the resulting container.