I have run into this issue as well. I can make things behave but it’s a little time consuming, I’ll look into making a bug report.
To fix the display of your post go to the HTML view and find the lines that relate to the images. Find the entries that include:
data-size="600x800"
and change them to:
data-size="800x600"
Obviously substituting your own image size. Things will then display properly.