Custom Icons for Quick Actions
The trick is to have the file end in ‘Template’, like ‘MyWorkflowIconTemplate.tiff’. But that’s not all there is to it. When you add a custom icon through Automator, it automatically gets renamed into ‘workflowCustomImage.png’. So no matter what you name your file, it won’t matter.
To fix this, add a custom icon to your Quick Action in Automator, save, switch to Finder and navigate to /Users/yourname/Library/Services/, where your newly saved Quick Action will end up. There, right-click your Quick Action, select ‘Show Package Contents’, and navigate into Resources, where your icon file will be. Rename it to ‘workflowCustomImageTemplate.png’. Now, navigate into Contents and open Info.plist. Look for <key>NSIconName</key> and change ‘workflowCustomImage’ to ‘workflowCustomImageTemplate’. Save.
You can use Quick Actions with both DropDMG and EagleFiler. The main catch, from my perspective, is that Finder accepts click-through for them. So if you have a habit of bringing Finder windows to the front by clicking near the bottom-right, be aware that you may accidentally invoke a Quick Action.
Gansrigler also has a tip for making the right kind of TIFF file for the Touch Bar. However, you don’t have to write code to do this. You can make a multi-representation TIFF using tiffutil.
