image_to_string returns nothing sometimes

[lolon...@gmail.com]

Hi all,

I'm new to pytesseract.

I tried to use image_to_string method with two identical image. Image A is saved by screen grab and then Image.save. I applied image_to_string to A, it returns nothing. 

Then I use photoshop to load the same image and save as a copy, imgae B. I applied image_to_string to B, it worked !!!

It's so strange, I don't know why. I tried several times, every time it only works on the copy saved by photoshop or other software such as sceenshot app.