Add --image/-im section to the readme

README.md

@@ -17,6 +17,7 @@ requests.
   - [Uninstall](#uninstall)
   - [Fonts](#fonts)
   - [Colors](#colors)
+  - [Images](#images)
   - [Testing Without Rebooting](#testing-without-rebooting)
 - [What does Matter do to my system
   files?](#what-does-matter-do-to-my-system-files)
@@ -154,6 +155,19 @@ the syntax:
 ./matter.py -hl FFC107 -fg white -bg 2196f3 -ic pink
 ```
 
+## Images (unfinished)
+
+You can specify a background image with `--image/-im`, the supported image
+formats/extensions are PNG, JPG, JPEG, and TGA. This feature is considered
+*unfinished* because it does not yet work as well as it could *(see
+[#57](https://github.com/mateosss/matter/pull/57))*
+
+Here is an example of the syntax:
+
+```sh
+./matter.py -im ~/Pictures/some-cool-image-that-has-good-contrast-with-my-text-color.png
+```
+
 ## Testing Without Rebooting
 
 If you install the `pip` package

matter.py

@@ -23,6 +23,7 @@
 
 # Logging utils
 
+
 def color_string(string, fg=None):
     COLORS = {  # List some colors that may be needed
         "red": "\033[31m",
@@ -323,11 +324,9 @@ def prepare_source_dir():
     # Image checks
     if image:
         if not exists(image):
-            error(
-                f"{image} does not exist!")
-        if os.path.splitext(image)[1] not in ('.png', '.tga', '.jpg', '.jpeg'):
-            error(
-                f"Background image must be one of .png, .tga, .jpg or .jpeg formats.")
+            error(f"{image} does not exist")
+        if os.path.splitext(image)[1] not in (".png", ".tga", ".jpg", ".jpeg"):
+            error(f"Background image must be one of .png, .tga, .jpg or .jpeg formats.")
         image_name = basename(image)
         copyfile(image, f"{INSTALLATION_SOURCE_DIR}/{image_name}")
         if background:
@@ -632,6 +631,7 @@ def do_set_icons():
         f"{GRUB_MKCONFIG_PATH} succesfully patched, icons will now persist between grub updates."
     )
 
+
 def install_hookcheck():
     info(f"Create hook check script")
     with open(HOOKCHECK_TEMPLATE_PATH, "r", newline="") as f:
@@ -737,7 +737,7 @@ def parse_args():
         "--image",
         "-im",
         type=str,
-        help=f"image file to use as background",
+        help=f"image file to use as background, supported extensions: PNG, JPG, JPEG, TGA",
     )
     parser.add_argument(
         "--iconcolor",