diff --git a/renovate.json b/renovate.json
index 5feee5c..4b8fe91 100644
--- a/renovate.json
+++ b/renovate.json
@@ -14,8 +14,8 @@
     {
       "fileMatch": ["^.*\\.nix$"],
       "matchStrings": [
-        "image\\s*=\\s*\"(?<depName>[^:]+):(?<currentValue>[^@\"]+)(?:@(?<currentDigest>sha256:[a-f0-9]+))?",
-        "Image\\s*=\\s*\"(?<depName>[^:]+):(?<currentValue>[^@\"]+)(?:@(?<currentDigest>sha256:[a-f0-9]+))?"
+        "image\\s*=\\s*\"(?<depName>[^\"]+):(?<currentValue>[^\"]+)(@(?<currentDigest>sha256:[a-f0-9]+))?\"",
+        "Image\\s*=\\s*\"(?<depName>[^\"]+):(?<currentValue>[^\"]+)(@(?<currentDigest>sha256:[a-f0-9]+))?\""
       ],
       "datasourceTemplate": "docker"
     }