There is no reason for ThinLinc and rdesktop to, by default, disable the wallpaper for connections to a Windows server. We don't do this for normal Linux desktops and if the administrator wants to do this it's better enforced by a server-side group policy.
This was fixed in rdesktop vendordrop (r32951). The default session size was also increased from 800x600 to 1024x768. Upstream commit: https://github.com/rdesktop/rdesktop/commit/d037db10861eb119c50e7dad4d8666b786d33a2f
Works well. Verified to be working on Windows Server 2008 R2, 2012 R2 and 2016.
Note: The fix was to change the default value for the experience flag (-x) to rdesktop. Aside what's described in the man-pages, the following bits can be manually controlled by this flag: disable wallpaper 0b00000001 disable full window drag 0b00000010 disable menu animations 0b00000100 disable theming 0b00001000 disable cursor shadow 0b00100000 disable cursor settings 0b01000000 enable font smoothing 0b10000000 These can be set individually by giving a hexadecimal value to the -x flag. So for example, if you want to disable wallpaper, full window drag, menu animations and enable font smoothing (0b10000111 = 0x87): tl-run-rdesktop -x 0x87
