Add info to readme

.gitignore

@@ -21,4 +21,7 @@
 go.work
 
 # macOS
-.DS_Store
+.DS_Store
+
+# binary
+resizer

README.md

@@ -1,2 +1,25 @@
 # Resizer
 Easily resize images
+
+## Usage:
+`Usage: ./resizer <image_path> <size> ...`
+
+Sizes can be a single number, to resize into a square:
+`./resizer <image_path> 1024 ...`
+
+Or they can be exact, using 'x' as a splitter:
+`./resizer <image_path> 500x300 ...`
+
+Individual sizes are separated by a space.
+
+Add as many sizes as you want, mixing between both square & exact measurements.
+
+Supports JPEG, PNG, and GIF.
+
+Results will be stored in the same directory as the input file, with the size at the end:
+
+`./resizer /path/to/my/image.png 1024`
+
+will result in a file named 
+
+`/path/to/my/image_1024x1024.png`