Wrong axis scaling in .plot_image

When I call .plot_image() on epochs data, the x axis (time) is correctly shown in seconds.

However, when I call .plot_image() on evoked data (=epochs.average()), the x axis (again, time) is incorrectly shown in milliseconds (although the values indicate seconds).

Having used some of the plotting functions, I have also realized that the labeling for the time axis is not always either in milliseconds or in seconds but rather this changes from function to function and apparently depending on the object that I call the function on (see above).

Apart from fixing the issue with evoked.plot_image(), maybe it would be better to use consistent labeling for the time axis? Or are there reasons that would speak against this consistency?

Pictures to show what I mean (the data is always the same): evoked.plot_image() --> time axis label should be “seconds” … or x_axis_values *= 1000

epochs.plot_image() --> again, this is a correct example … working with an epochs instead of an evoked object

evoked.plot_joint() --> another correct example, this time with an evoked object again. However why is it in milliseconds now?

[jona-sassenhagen]

There is a PR for evoked.plot_image underway in #5010, I can also set it to s there?

[larsoner]

And it looks like there is a bug in that image plot, too. Zero should be white (middle of colorbar).