[Georgio]

Код:

@Echo Off
Set MyDir=C:\lab1\wingraf
Set Ras=.gif

Call :_subdir %MyDir% %Ras%
Echo %Size%
Pause>Nul
Exit

:_subdir
For /R %1 %%s In (*) Do if %%~xs==%2 SET /A Size+=%%~zs
EXIT /B