Hi,
I would recommend removing the image as it has some sensitive data.
As for the question. It is not truncating the data, but using a different method to send the data. When the image request is too large, the library changes the method from GET to POST. In the screenshot you have shared, you can see that the Request Method is POST.
In short, GET method sends data through the URL, while POST transfers it through the message body. For more information, you can read here: http://www.differencebetween.info/difference-between-get-and-post-method