Ah, looks like rubberduck set them up so the overflowing tiles are adjacent. I was wrong about the offsets. It's a 16x16 spritesheet with some tiles having overflow. So, here's how to split them out into individual tiles:

1. open https://www.piskelapp.com
2. click the "create sprite" button in the upper-right corner
3. cick the folder icon "Import" along the right side
4. click the "browse images" button beneath "Import from picture"
5. navigate to your local copy of colony-other-ready.png and select/open it.
6. on the Import and Merge dialog, select "Import as Spritesheet"
7. enter a frame size of 16x16 with an offset of 0x0
8. click "import"
9. "This will replace your current animation. Are you sure you want to continue?" Yes.
10. click the mountain icon "Export" along the right side.
11. on the export dialog, find the [ Gif | PNG | Zip | Others ] tabs, select the "Zip" tab.
12. click on the "Download ZIP" button at the bottom of the dialog.
13. save your zip file somewhere you'll remember, then open and extract all the individual sprites!