The following images are under a CC0 license by their respective creators:

bokeh.jpg | StockSnap @ pixabay
clouds.jpg | Ryan McGuire @ Gratisography
forest_lake.jpg | Alex Krivec @ unsplash
forest_railroad.jpg
forest_river.jpg  | Ryan McGuire @ Gratisography
lemon_water.jpg | kirahoffmann @ pixabay
mountain_beach.jpg | Photographer: @eberhardgross
mountain_cabin.jpg | Photographer: @eberhardgross
mountain_lake.jpg | Photographer: @eberhardgross
mountain_range.jpg | tpsdave @ pixabay
mountian_reflections.jpg | Photographer: @eberhardgross
mountain_river.jpg | Photographer: Anton Hooijdonk
mountain_sky.jpg | Photographyer: Daniel Leone
mountain_valley.jpg | Photographer: @eberhardgross
ocean_front.jpg | Photographer: David Whiteford
park_lake.jpg | Photographer: @eberhardgross
rainy_sidewalk.jpg | Photographer: Guiliamar @ pixabay
red_leaves.jpg | Photographer: Onur Kurtic @ http://onurkurticphotography.com/?ref=pexels
ripple_reflections.jpg | Photographer: strikers @ pixabay
snowy_cabin.jpg | Photographer: lutz6078 @ pixabay
snowy_mountains.jpg  | Photographer Philip Bunkens @ unsplash
wave.jpg | Photographer Austin Scmid @ unsplash
wood_panels.jpg | Photographer Picthai.com

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