Thanks for the pointers, they were all relevant to my setup.

However, now I got stuck at

`x = solve_image(evaluator, iterations, x)`

Which gives a rather lengthy error message, which I included (shortened).

Anyone has oberserved this as well?

```
InvalidArgumentError Traceback (most recent call last)
<ipython-input-44-d733ab4b440a> in <module>()
----> 1 x = solve_image(evaluator, iterations, x)
<ipython-input-25-d3d1b9a0479e> in solve_image(eval_obj, niter, x)
2 for i in range(niter):
3 x, min_val, info = fmin_l_bfgs_b(eval_obj.loss, x.flatten(),
----> 4 fprime=eval_obj.grads, maxfun=20)
5 x = np.clip(x, -127,127)
6 print('Current loss value:', min_val)
[...SNIP...]
/mounts/Users/myusername/.local/lib/python3.5/site-packages/tensorflow/python/client/session.py in _do_call(self, fn, *args)
1338 except KeyError:
1339 pass
-> 1340 raise type(e)(node_def, op, message)
1341
1342 def _extend_graph(self):
InvalidArgumentError: Incompatible shapes: [64] vs. [128]
[[Node: add_1 = Add[T=DT_FLOAT, _device="/job:localhost/replica:0/task:0/gpu:0"](add, Mean_4)]]
[[Node: gradients_2/block1_conv1_1/convolution_grad/Conv2DBackpropInput/_301 = _Recv[client_terminated=false, recv_device="/job:localhost/replica:0/task:0/cpu:0", send_device="/job:localhost/replica:0/task:0/gpu:0", send_device_incarnation=1, tensor_name="edge_459_gradients_2/block1_conv1_1/convolution_grad/Conv2DBackpropInput", tensor_type=DT_FLOAT, _device="/job:localhost/replica:0/task:0/cpu:0"]()]]
Caused by op 'add_1', defined at:
File "<string>", line 1, in <module>
File "/usr/lib/python3/dist-packages/IPython/kernel/zmq/kernelapp.py", line 469, in main
app.start()
[...SNIP...]
File "/mounts/Users/myusername/.local/lib/python3.5/site-packages/tensorflow/python/framework/ops.py", line 1204, in __init__
self._traceback = self._graph._extract_stack() # pylint: disable=protected-access
InvalidArgumentError (see above for traceback): Incompatible shapes: [64] vs. [128]
[[Node: add_1 = Add[T=DT_FLOAT, _device="/job:localhost/replica:0/task:0/gpu:0"](add, Mean_4)]]
[[Node: gradients_2/block1_conv1_1/convolution_grad/Conv2DBackpropInput/_301 = _Recv[client_terminated=false, recv_device="/job:localhost/replica:0/task:0/cpu:0", send_device="/job:localhost/replica:0/task:0/gpu:0", send_device_incarnation=1, tensor_name="edge_459_gradients_2/block1_conv1_1/convolution_grad/Conv2DBackpropInput", tensor_type=DT_FLOAT, _device="/job:localhost/replica:0/task:0/cpu:0"]()]]
```