diff --git a/doc/api/next_api_changes/deprecations/XXXXX-AL.rst b/doc/api/next_api_changes/deprecations/25484-AL.rst
similarity index 51%
rename from doc/api/next_api_changes/deprecations/XXXXX-AL.rst
rename to doc/api/next_api_changes/deprecations/25484-AL.rst
index 41a0c09bb22c..d6989dcea25f 100644
--- a/doc/api/next_api_changes/deprecations/XXXXX-AL.rst
+++ b/doc/api/next_api_changes/deprecations/25484-AL.rst
@@ -1,3 +1,4 @@
 ``RendererAgg.tostring_rgb`` and ``FigureCanvasAgg.tostring_rgb``
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-... are deprecated with no replacement.
+... are deprecated with no direct replacement. Consider using ``buffer_rgba``
+instead, which should cover most use cases.
diff --git a/lib/matplotlib/backends/backend_agg.py b/lib/matplotlib/backends/backend_agg.py
index 3d7dfa57a82e..179a00ac64bc 100644
--- a/lib/matplotlib/backends/backend_agg.py
+++ b/lib/matplotlib/backends/backend_agg.py
@@ -280,7 +280,7 @@ def buffer_rgba(self):
     def tostring_argb(self):
         return np.asarray(self._renderer).take([3, 0, 1, 2], axis=2).tobytes()
 
-    @_api.deprecated("3.8")
+    @_api.deprecated("3.8", alternative="buffer_rgba")
     def tostring_rgb(self):
         return np.asarray(self._renderer).take([0, 1, 2], axis=2).tobytes()
 
@@ -415,7 +415,7 @@ def get_renderer(self, cleared=False):
             self.renderer.clear()
         return self.renderer
 
-    @_api.deprecated("3.8")
+    @_api.deprecated("3.8", alternative="buffer_rgba")
     def tostring_rgb(self):
         """
         Get the image as RGB `bytes`.