Sending images via Fernschreiber doesn’t work for me, too (Sailfish versions 4.5.0.18 and 4.5.0.19)
Don’t know if it’s device specific or a general issue.
Sending the images via fernschreiber as file works though.
Edit: Seems to be device specific. Sending images from my XPeria 10Plus via Fernschreiber works on 4.5.0.19.