I opened the demo project in GMS2 IDE v2.3.3.574 (runtime v2.3.3.437) and the project file did not include the sprites needed to run the project. 

I can run the application demo just fine, but I'd love to know the dimensions / image ratios / details of the sprites and what sprites it uses so I can properly implement it quickly

Thanks!

I just checked and the demo project definitely contains sprites - you can extract the YYZ with an archive manager and see for yourself. An alternative is to take PNGs from git

I'll see if I can import them from git. I forget an error occurred when importing, here's the screenshot 

So it seemed the sprite WERE there in the files, but for some reason they just didn't import. 

So I re-added them to the project with the same name. All seem to work, except for the border. I added them with default settings and top-left origin point. I'm not sure why its doing this compared to the application demo, it works fine there. 

The border sprite is a 9-slice with the middle part disabled.

I have now released a new version (1.0.1a) that has the sprites included in the packed extension

Awesome! Thanks!