This image comes from the website http://fyfluiddynamics.com which is a blog created and authored by Nicole Sharp describing all sorts of fluid dynamic phenomena. This image is described as:

“Dyed isopropyl alcohol atop a thin layer of acrylic medium spreads in a fractal fingering pattern. Although the shapes are reminiscent of the viscous fingers seen in in the Saffman-Taylor instability, these patterns are most likely a result of surface tension. The lower surface tension of the alcohol causes Marangoni forces to pull it outward. The branching shapes indicate an instability, likely driven by surface tension, but the details of the mechanism behind it are unclear. (Image credits: J. Nahabetian)”

Nahabetian, J. (2018, May 8). FYFD. Retrieved May 8, 2018, from http://fyfluiddynamics.com/image/173704478618