unsupported operand type(s) about brother_ql

[pklaus]

The very first line in your console output is from the brother_ql_create tool. It's letting you know that it has to resize your picture, because you don't provide it with the ideal pixel dimensions right away. If you can, try to stick to the pixel dimensions that brother_ql_info list-label-sizes tells you.

The following lines in your output are from the tool brother_ql_print. Let me quote the print section of the README:

[...] tool brother_ql_print (Py3 only) [...]

It's just not Python 2 compatible. (Sending the data should work, but interpreting the response fails.)
I'm surprised how many out there are still using Python 2. :) I'm currently not planning to make the tool Python 2 compatible but if there will be more issues coming in like this, I might consider porting it back.

Thanks again for the report and let me know if you can imagine any way to improve the library.