The process for vectorizing this image was mainly through the use of the image trace feature of illustrator. I used image trace and then limited the colors to 16 to essentially reduce the detail and acquire a more painterly vibe. After everything was vectorized, I used the recolor tool, and then advanced options, to modify the colors of the vectorization, allowing me to give the peaks of the mountains snow, using high values of a blue hue. I was aiming for season of winter is this picture, using the blues and snow whites to convey mood and temperature. 

For the spring focused piece, I changed all the colors be more green and lively, to reflect the colors of the season. I changed the general color scheme using the recolor wheel, and then used advanced settings to go in and change the sky from greens to vibrant blues. 

For this piece, I wanted to convey fall, which I did by using warmer, more orange colors in both the ground and the sky. I simply took the original image trace vectorization, and moved the colors from the original blues to the yellow/oranges to result in this look.

Original image credits:

https://unsplash.com/photos/landscape-photography-of-green-mountain-8wz1Q4Q_XAgk