decoded message only "ÿÿÿÿÿÿÿÿÿÿÿÿÿÿ"

[achraf-mabrouk]

i just trying to encode text and put it in the image but after decode the image : Text value: ÿÿÿÿÿÿÿÿÿÿÿÿÿÿÿ
which is not correct.
i'm using Python3.5

[abnormalhare]

The bit code for that is just a bunch of repeated ones. Seems like it's just a white picture.