This post isn’t about how you format your issue (story, card, etc…).
As a maker, I want my acceptance criteria clear and trackable so that I can deliver the correct functionality.
Clear is clear, trackable is what I’d like to emphasize.
Referencing external files or tools in your acceptance criteria eliminates your ability to accurately track the level of effort when the criteria changes during development.
All information required to complete the issue should be in the issue. You really want an immutable record of events to understand the level of effort that goes into your development process.
While it may seem easier to share that Dropbox link to the file with the requirements or even that Abstract URL with your annotated screens, it really complicates the process.
Copy the requirements into the description and attach those screens to the issue.