Tutorial uses old logo

[LiberalArtist]

The logo should be updated at:

slideshow/slideshow-exe/slideshow/initial-ones.rkt

Lines 25 to 26 in 5e395e6

	(size-in-pixels
	(bitmap (collection-file-path "PLT-206.png" "icons")))

I don't immediately see the current logo in the icons collection, and I'm not sure if it should be added there or here.

[LiberalArtist]

The old logo is used again at:

slideshow/slideshow-exe/slideshow/tutorial-show.rkt

Lines 359 to 363 in 5e395e6

	(slide
	#:title "Bitmaps"
	(para "For example, the" (code bitmap) "function loads a bitmap to display")
	(blank)
	(bitmap (build-path (collection-path "icons") "plt.gif")))