However, there was a trick : the diagram had a really bad resolution, was almost impossible to read :( But because I really wanted to make this butterfly I did my best to decipher it. Long story short, this is the result :) Not so bad in my opinion. I also made some pictures and wrote down what exactly i was doing, and I thought to share it with you, in case you want to make this pretty crocheted butterfly too.
I am new at writting down patterns so do let me know if you have problems following the instructions.