The JSON standard is pretty clear that strings are Unicode code points (could be UTF8, 16 or 32). Elixir strings are UTF8 and that’s the contract. So I would expect failure iii the string is not UTF8.
(Section 9) A string is a sequence of Unicode code points wrapped with quotation marks (U+0022).
Therefore the best solution is for the source system to correct its invalid JSON. Since I suspect you’ll say that’s not going to happen, any solution will need to work around the non-standard binary data and your Python approach may be as good as any.
It’s really unfortunate to see binary data (the PNG image in this case) being passed off as a string. It should at least be encoded in some fashion.
