I see we can improve the welcome screen when the example files can't be found. We handle that in the menu that comes up when you single click the example item, but if you double click an item it tries to open even if the example file doesn't exist. We'll show an error dialog instead.
I'm not sure why you don't have the example files, but you can find them in the Spine download. You can also download them from the example web pages:
Spine: Example Projects
Those pages explain in detail how the projects are setup and how they work. That can be very helpful if you explore the project in Spine as you read the page for that project.
If you don't have a JSON or binary data file, then Import Data is not what you want. There are two ways to get your images into Spine:
1) Set the path on the Images node in the tree:
Images - Spine User Guide
Your images will then show up under the Images node. You can drag them into the viewport or use the Set Parent button. This is the manual process though, read on if you are using Photoshop.
2) You can run the PhotoshopToSpine script in Photoshop to generate a Spine JSON file. Then you can use Import Data to bring your images into Spine at the same locations they were in Photoshop, which is more precise and saves a lot of time compared to positioning them manually.
