diff --git a/cf-lib/data/Entity.lua b/cf-lib/data/Entity.lua
index 4a21072..10172ad 100644
--- a/cf-lib/data/Entity.lua
+++ b/cf-lib/data/Entity.lua
@@ -26,4 +26,21 @@ Entity.collisionBox = function(width, height, margin)
     }
 end
 
+--- Sets the file name on a picture considering various formats.
+--- If sheets or layers are found, use the optional param to select the right one.
+--- @param sprite table The sprite to replace the filename in
+--- @param filename string The new filename
+--- @param sheetLayer number The sheet or layer index to use. Defaults to 1.
+Entity.setFilename = function(sprite, filename, sheetLayer)
+    if sprite.filename then
+        sprite.filename = filename
+    elseif sprite.sheet then
+        sprite.sheet.filename = filename
+    elseif sprite.sheets then
+        sprite.sheets[sheetLayer or 1].filename = filename
+    elseif sprite.layers then
+        sprite.layers[sheetLayer or 1].filename = filename
+    end
+end
+
 return Entity
\ No newline at end of file