An abridged 45-minute version (the original is 118 minutes) was released on the YouTube channel. While not the full feature, it gives the gist of the plot.
The title serves as a metaphor for these women—fragile yet resilient "butterflies" trapped in the "grey" monotony and harshness of both prison and society. or where you can watch this film nonton film thailand butterfly in grey work
Given the ambiguity, your best bet is to look for Thai films with "Butterfly" in the title or films that match the aesthetic of grey, melancholic romance. An abridged 45-minute version (the original is 118