diff --git a/README.md b/README.md
index bdc72f3..e7db7eb 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,6 @@ gen_png.py [OPTION]
 -h, --help                      Shows this help message.
 -a, --all                       Generate PNGs of all SVGs.
 -s, --specific S [S ...]        Generate PNGs for each S in the "svg" folder. The '.svg' suffix is optional.
--r, --resolution R [R ...]      Custom resolutions that will be generated instead of the defaults.
+-r, --resolution R [R ...]      Custom resolutions that will be generated instead of the defaults (72, 512, 1024).
 -g, --git                       Generates PNGs of SVGs that changed since last auto tag and creates a git commit with them. Requires 'git' to be installed and located in PATH.
 ```
diff --git a/gen_png.py b/gen_png.py
index 0f923ea..056e1eb 100755
--- a/gen_png.py
+++ b/gen_png.py
@@ -93,7 +93,7 @@ def main():
                              help="Generate PNGs for each S in the \"svg\" folder. " +
                                   "The '.svg' suffix is optional.")
     parser.add_argument("-r", "--resolution", metavar='R', type=int, nargs="+",
-                        help="Custom resolutions that will be generated instead of the defaults.")
+                        help="Custom resolutions that will be generated instead of the defaults (72, 512, 1024).")
     mutex_group.add_argument("-g", "--git", action="store_true",
                              help="Generates PNGs of SVGs that changed since last auto tag and creates a git commit with them. " +
                                   "Requires 'git' to be installed and located in PATH.")