The SoftLayer_Ticket::addAttachedFile method fails when tried to attach images, the following message is raised
SoftLayerAPIError: SoftLayerAPIError(SoftLayer_Ticket): No valid authentication headers found.

Requirements:
Python 2.6 or 2.7
SoftLayer API python client (3.3.1)

It seems to be a problem related to Python 2 since using Python 3 or higher the SoftLayer_Ticket::addAttachedFile method works.

The problem is reproduced with the following code

import SoftLayer
import pprint

apiUsername = 'set-me'
api_key = 'set-me'

apiUsername = 'set-me'
api_key = 'set-me'
ticket_id = set-me
client = SoftLayer.Client(username= apiUsername,api_key=api_key)

f = open('/path/to/image.png', 'rb')
filecontents = f.read()
attachedFile = { 'data': filecontents, 'filename': 'image.png'}
result = client['Ticket'].addAttachedFile(attachedFile, id=ticket_id)
pprint.pprint(result)

Here is the traceback for the Python issue.

Traceback (most recent call last):
File "addAttachedFile.py", line 24, in
result = client['Ticket'].addAttachedFile(attachedFile, id=13410275)
File "/usr/local/lib/python2.7/dist-packages/SoftLayer/API.py", line 351, in call_handler
return self(name, _args, *_kwargs)
File "/usr/local/lib/python2.7/dist-packages/SoftLayer/API.py", line 319, in call
return self.client.call(self.name, name, _args, *_kwargs)
File "/usr/local/lib/python2.7/dist-packages/SoftLayer/API.py", line 184, in call
return transports.make_xml_rpc_api_call(request)
File "/usr/local/lib/python2.7/dist-packages/SoftLayer/transports.py", line 137, in make_xml_rpc_api_call
ex.faultCode, ex.faultString)
SoftLayer.exceptions.SoftLayerAPIError: SoftLayerAPIError(SoftLayer_Ticket): No valid authentication headers found.