diff --git a/CHANGELOG.md b/CHANGELOG.md
index 74cd714..8223b63 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 ## [Unreleased]
 ### Fixed
  - Fix crash caused by the Steam shortcut configuration file containing extra data after the VDF section
+ - Fix differently sized custom app icons breaking the layout in the app selector
 
 ## [1.10.3] - 2023-05-06
 ### Added
diff --git a/setup.cfg b/setup.cfg
index a6bb746..0f94fd8 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -30,6 +30,7 @@ include_package_data = True
 install_requires =
     setuptools  # Required for pkg_resources
     vdf>=3.2
+    Pillow
 setup_requires =
     setuptools-scm
 python_requires = >=3.6
diff --git a/src/protontricks/gui.py b/src/protontricks/gui.py
index 4148ee2..b30e7b6 100644
--- a/src/protontricks/gui.py
+++ b/src/protontricks/gui.py
@@ -10,9 +10,14 @@
 from subprocess import PIPE, CalledProcessError, run
 
 import pkg_resources
+from PIL import Image
 
 from .config import get_config
 from .flatpak import get_inaccessible_paths
+from .util import get_cache_dir
+
+APP_ICON_SIZE = (32, 32)
+
 
 __all__ = (
     "LocaleError", "get_gui_provider", "select_steam_app_with_gui",
@@ -60,19 +65,47 @@ def _get_appid2icon(steam_apps, steam_path):
         )
     )
 
-    icon_dir = steam_path / "appcache" / "librarycache"
-    existing_names = [path.name for path in icon_dir.glob("*")]
+    steam_icon_dir = steam_path / "appcache" / "librarycache"
+    existing_names = [path.name for path in steam_icon_dir.glob("*")]
+
+    protontricks_icon_dir = get_cache_dir() / "app_icons"
+    protontricks_icon_dir.mkdir(exist_ok=True)
 
     appid2icon = {}
 
     for app in steam_apps:
         # Use library icon for Steam apps, fallback to placeholder icon
         # for non-Steam shortcuts and missing icons
-        appid2icon[app.appid] = (
-            icon_dir / f"{app.appid}_icon.jpg"
-            if f"{app.appid}_icon.jpg" in existing_names
-            else placeholder_path
-        )
+        icon_cache_path = protontricks_icon_dir / f"{app.appid}.jpg"
+        original_icon_path = steam_icon_dir / f"{app.appid}_icon.jpg"
+
+        # What path to actually use for the app selector. Defaults to
+        # the original icon path
+        final_icon_path = placeholder_path
+
+        icon_exists = f"{app.appid}_icon.jpg" in existing_names
+        resize_icon = False
+
+        # Resize icons that have a non-standard size to ensure they can be
+        # displayed consistently in the app selector
+        if icon_exists:
+            final_icon_path = original_icon_path
+
+            with Image.open(original_icon_path) as img:
+                resize_icon = img.size != APP_ICON_SIZE
+
+                # Resize icons that have a non-standard size to ensure they can
+                # be displayed consistently in the app selector.
+                if resize_icon:
+                    logger.info(
+                        "App icon %s has unusual size, resizing",
+                        original_icon_path
+                    )
+                    resized_img = img.resize(APP_ICON_SIZE)
+                    resized_img.save(icon_cache_path)
+                    final_icon_path = icon_cache_path
+
+        appid2icon[app.appid] = final_icon_path
 
     return appid2icon
 
diff --git a/tests/test_gui.py b/tests/test_gui.py
index 13d8c8f..e933933 100644
--- a/tests/test_gui.py
+++ b/tests/test_gui.py
@@ -2,6 +2,7 @@
 
 import pytest
 from conftest import MockResult
+from PIL import Image
 
 from protontricks.gui import (prompt_filesystem_access,
                               select_steam_app_with_gui,
@@ -100,8 +101,9 @@ def test_select_game_icons(
         ]
 
         # Create icons for game 1 and 3
-        (steam_dir / "appcache" / "librarycache" / "10_icon.jpg").touch()
-        (steam_dir / "appcache" / "librarycache" / "30_icon.jpg").touch()
+        for appid in (10, 30):
+            Image.new("RGB", (32, 32)).save(
+                steam_dir / "appcache" / "librarycache" / f"{appid}_icon.jpg")
 
         gui_provider.mock_stdout = "Fake game 2: 20"
         select_steam_app_with_gui(steam_apps=steam_apps, steam_path=steam_dir)
@@ -112,6 +114,41 @@ def test_select_game_icons(
         assert b"icon_placeholder.png\nFake game 2" in input_
         assert b"librarycache/30_icon.jpg\nFake game 3" in input_
 
+    def test_select_game_icons_ensure_resize(
+            self, gui_provider, steam_app_factory, steam_dir, home_dir):
+        """
+        Select a game using the GUI. Ensure custom icons with sizes other than
+        32x32 are resized.
+        """
+        steam_apps = [
+            steam_app_factory(name="Fake game 1", appid=10)
+        ]
+
+        Image.new("RGB", (64, 64)).save(
+            steam_dir / "appcache" / "librarycache" / "10_icon.jpg"
+        )
+
+        gui_provider.mock_stdout = "Fake game 1: 10"
+        select_steam_app_with_gui(steam_apps=steam_apps, steam_path=steam_dir)
+
+        # Resized icon should have been created with the correct size and used
+        resized_icon_path = \
+            home_dir / ".cache" / "protontricks" / "app_icons" / "10.jpg"
+        assert resized_icon_path.is_file()
+        with Image.open(resized_icon_path) as img:
+            assert img.size == (32, 32)
+
+        input_ = gui_provider.kwargs["input"]
+
+        assert f"{resized_icon_path}\nFake game 1".encode("utf-8") in input_
+
+        # Any existing icon should be overwritten if it already exists
+        resized_icon_path.write_bytes(b"not valid")
+        select_steam_app_with_gui(steam_apps=steam_apps, steam_path=steam_dir)
+
+        with Image.open(resized_icon_path) as img:
+            assert img.size == (32, 32)
+
     def test_select_game_no_choice(
             self, gui_provider, steam_app_factory, steam_dir):
         """