Some newer episodes use .png thumbnails, and in these cases there is no .jpg thumbnail available.
This PR adds support for querying playlist.json to determine the thumbnail extension.
Examples:
Boy Girl Dog Cat Mouse Cheese (m0009xgc)
Season 1: .jpg
Season 2
Episodes 1-4: .jpg
Episodes 5+ .png
Programs in this series using .png (as of 2022)
```
Boy Girl Dog Cat Mouse Cheese - 5. Gametime, Go!, CBBC, m00134dj
Boy Girl Dog Cat Mouse Cheese - 6. Junked, CBBC, m0013c8h
Boy Girl Dog Cat Mouse Cheese - 7. Go Fetch, CBBC, m0013cc0
Boy Girl Dog Cat Mouse Cheese - 8. Tricked Out, CBBC, m0013ccv
Boy Girl Dog Cat Mouse Cheese - 9. The Room Mate, CBBC, m0013cdr
Boy Girl Dog Cat Mouse Cheese - 10. Chili Overload, CBBC, m0013cgm
Boy Girl Dog Cat Mouse Cheese - 11. X Marks the Spot, CBBC, m0013mcp
Boy Girl Dog Cat Mouse Cheese - 12. Lights! Camera! Action!, CBBC, m0013mfb
Boy Girl Dog Cat Mouse Cheese - 13. Dog Days, CBBC, m0013mgl
Boy Girl Dog Cat Mouse Cheese - 14. Narwhal Day, CBBC, m0013mhl
Boy Girl Dog Cat Mouse Cheese - 15. Bobblehead Heads, CBBC, m0013mjl
Boy Girl Dog Cat Mouse Cheese - 16. Mouse Steps, CBBC, m0013vb6
Boy Girl Dog Cat Mouse Cheese - 17. Gramps' Gauntlet of Greatness, CBBC, m0013vcy
Boy Girl Dog Cat Mouse Cheese - 18. Who Let the Weredogs Out, CBBC, m0013vbz
Boy Girl Dog Cat Mouse Cheese - 19. Staycation, CBBC, m0013vf6
Boy Girl Dog Cat Mouse Cheese - 20. The Swapper, CBBC, m0013vmn
Boy Girl Dog Cat Mouse Cheese - 21. Nothing but the Truth, CBBC, m00142ff
Boy Girl Dog Cat Mouse Cheese - 22. Gramps Date, CBBC, m00142fz
Boy Girl Dog Cat Mouse Cheese - 23. Grin and Parrot, CBBC, m00142j7
Boy Girl Dog Cat Mouse Cheese - 24. Future Proof, CBBC, m00142jl
Boy Girl Dog Cat Mouse Cheese - 25. For the Birds, CBBC, m00142jx
```
Some newer episodes use
.pngthumbnails, and in these cases there is no.jpgthumbnail available. This PR adds support for queryingplaylist.jsonto determine the thumbnail extension.Examples:
Boy Girl Dog Cat Mouse Cheese (m0009xgc).jpg.jpg.pngPrograms in this series using
.png(as of 2022)