base64 to image, corrupt image

Question

I have this code:

with open("bla.png", "wb") as fh:
    fh.write(image.decode('base64'))

and this base64: https://pastebin.com/MKjEdmub The base64 code comes from a canvas from the front-end. I've verified that the string is exactly the same frontend and backend.

If I try to run the code the current base64 code it says: Error: Incorrect padding . I did a bit of research and it turns out that it needs a certain amount of bytes to be converted correctly, hence why it needs = at the end of the string. In this case it needs == at the end of the string. When I do that it converts fine, but the image is corrupt (unreadable).

When I use an online convertor, the current base64 works fine. When I add == it doesn't work in those as well.

I also tried with the decodestring function from the base64 library, but that gave the same error.

Answer 1

Using str.decode('base64') on your data works fine for me, did you remove the data:image/png;base64, header at the beginning? If I don't remove it I also get a padding error. The online tools that you've tried might check for this common syntax and remove it automatically before decoding.