WHY

@echo off
set "srcDir=D:\photos"
set "dstDir=D:\images"
pushd "%srcDir%\"
 
for %%i in (*.jpg *.bmp) do (
    set "name=%%~ni"
    setlocal enabledelayedexpansion
    set "fd=!dstDir!\!name:~0,1!"
    md "!fd!" 2>nul
    if not exist "!fd!\!name!%%~xi" (
        copy "!name!%%~xi" "!fd!\"
    ) else (
        set "n=1"
        call :Next "%%~xi"
        copy "!name!%%~xi" "!fd!\!name!(!n!)%%~xi"
    )
    endlocal
)
pause & exit
 
:Next
if exist "!fd!\!name!(!n!)%~1" (
    set /a n+=1
    goto :Next
)COPY