How to find out why FileZilla breaks files?

Question

FTP

Greetings!
Recently, FileZilla began to mock - it does not append to the end of the image file png, jpg 1 KB.
Exactly 1 KB! Pictures less than 1KB write completely.
It does not finish writing when loading, when unloading everything is ok.
This is only from Yubunta, from Windows everything is ok.
Updated to a newer version - same.
Tried on two different versions of vsFTPd - the same.
But from Windows the same zilla file - everything is ok.
Other managers are ok.
What can she not like?

Answer 1

perhaps the problem is in the wrong data transfer mode (there are ascii, binary and something else).
try different modes.