Add Check Properties Of An Image With sips as a Mac TIL

2026-11-04 18:03:28 +00:00 · 2026-11-04 10:37:03 -06:00
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+# Check Properties Of An Image With `sips`
+
+I [used Figma to create a basic design for a t-shirt
+screenprinting](https://bsky.app/profile/jbranchaud.bsky.social/post/3mz43v6asns2f).
+Before I sent the image asset off to the printer, I needed to verify a couple
+properties of the image where right.
+
+My first thought was that there is probably a way to do this with `ffmpeg`, but
+I intentionally asked Claude in a non-leading way how to do this. It surfaced a
+Mac-specific utility I'd never heard of -- `sips` (_Scriptable Image Processing
+System_).
+
+Sometimes it is hard to tell if an image exported correctly with transparent
+background (alpha channel). Part of how I was able to verify that was to point
+`sips` at the PNG file and ask if it has an alpha channel. The `-g` flag (short
+for _get property_) is the way to output a property like this.
+
+```bash
+❯ sips -g hasAlpha ~/Downloads/Untitled/orange-shirt-print-front.png
+/Users/lastword/Downloads/Untitled/orange-shirt-print-front.png
+  hasAlpha: yes
+```
+
+I then wanted to check that the dimensions of the image were right. I had
+carefully sized the canvas in Figma to correspond to specs required by the
+printer. Similar to above, I can use `-g` to grab the `pixelWidth` and
+`pixelHeight` properties of the image.
+
+Unfortunately the pixel dimensions of the exported PNG were not what I was
+expecting.
+
+```bash
+❯ sips -g pixelWidth -g pixelHeight ~/Downloads/Untitled/orange-shirt-print-front.png
+/Users/lastword/Downloads/Untitled/orange-shirt-print-front.png
+  pixelWidth: 1152
+  pixelHeight: 1536
+```
+
+I then found some additional export settings in Figma and tried again. Nailed
+it.
+
+```bash
+❯ sips -g pixelWidth -g pixelHeight ~/Downloads/Marty\ Supreme\ —\ 12\ ×\ 16\ in\ print.png
+/Users/lastword/Downloads/Marty Supreme — 12 × 16 in print.png
+  pixelWidth: 3600
+  pixelHeight: 4800
+```
+
+See `man sips` for more details.