diff --git a/pygmt/src/grdimage.py b/pygmt/src/grdimage.py
index 563872fe775..917932038b5 100644
--- a/pygmt/src/grdimage.py
+++ b/pygmt/src/grdimage.py
@@ -9,17 +9,18 @@
 from pygmt._typing import PathLike
 from pygmt.alias import Alias, AliasSystem
 from pygmt.clib import Session
-from pygmt.helpers import build_arg_list, fmt_docstring, use_alias
+from pygmt.helpers import build_arg_list, deprecate_parameter, fmt_docstring, use_alias
 
 __doctest_skip__ = ["grdimage"]
 
 
 @fmt_docstring
+@deprecate_parameter("bitcolor", "bit_color", "v0.18.0", remove_version="v0.20.0")
 @use_alias(
     C="cmap",
     D="img_in",
     E="dpi",
-    G="bitcolor",
+    G="bit_color",
     I="shading",
     Q="nan_transparent",
     n="interpolation",
@@ -109,7 +110,7 @@ def grdimage(  # noqa: PLR0913
         same size (rows and columns) as the input file. Specify **i** to
         use the PostScript image operator to interpolate the image at the
         device resolution.
-    bitcolor : str
+    bit_color : str
         *color*\ [**+b**\|\ **f**\].
         This parameter only applies when a resulting 1-bit image otherwise
         would consist of only two colors: black (0) and white (255). If so,
diff --git a/pygmt/src/image.py b/pygmt/src/image.py
index d389e7477d9..d911f2b47e7 100644
--- a/pygmt/src/image.py
+++ b/pygmt/src/image.py
@@ -8,12 +8,13 @@
 from pygmt._typing import PathLike
 from pygmt.alias import Alias, AliasSystem
 from pygmt.clib import Session
-from pygmt.helpers import build_arg_list, fmt_docstring, use_alias
+from pygmt.helpers import build_arg_list, deprecate_parameter, fmt_docstring, use_alias
 from pygmt.params import Box
 
 
 @fmt_docstring
-@use_alias(D="position", G="bitcolor")
+@deprecate_parameter("bitcolor", "bit_color", "v0.18.0", remove_version="v0.20.0")
+@use_alias(D="position", G="bit_color")
 def image(
     self,
     imagefile: PathLike,
@@ -74,7 +75,7 @@ def image(
         box is drawn using :gmt-term:`MAP_FRAME_PEN`. To customize the box appearance,
         pass a :class:`pygmt.params.Box` object to control style, fill, pen, and other
         box properties.
-    bitcolor : str or list
+    bit_color : str or list
         [*color*][**+b**\|\ **f**\|\ **t**].
         Change certain pixel values to another color or make them transparent.
         For 1-bit images you can specify an alternate *color* for the