diff --git a/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs b/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs
index 74571a068d..51978e14e0 100644
--- a/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs
+++ b/OpenRA.Mods.Common/Graphics/DefaultSpriteSequence.cs
@@ -37,6 +37,15 @@ namespace OpenRA.Mods.Common.Graphics
 				nodes.Remove("Defaults");
 				nodes = nodes.ToDictionary(kv => kv.Key, kv => MiniYaml.MergeStrict(kv.Value, defaults));
 
+				// Merge 'Defaults' animation image value. An example follows.
+				//
+				// - Before -
+				// stand:
+				// 	Facings: 8
+				//
+				// - After -
+				// stand: e1
+				// 	Facings: 8
 				foreach (var n in nodes)
 					n.Value.Value = n.Value.Value ?? defaults.Value;
 			}