What did you do?

I open a tiff file, I add tags to some of the images in it, then save

What did you expect to happen?

Save modifications

What actually happened?

The added tag isn't saved

What are your OS, Python and Pillow versions?

• OS: windows 7
• Python: 3.6
• Pillow: 5.1.0

from PIL import Image, TiffImagePlugin

im = Image.open("test.tiff")
im.seek(6)
info = TiffImagePlugin.ImageFileDirectory()
info[56] = 54
info.tagtype[56] = 3
im.save("test_out.tiff", save_all=True, tiffinfo = info)