Well this won't give you the file size per sub-folder that you're now asking about, but it will give you the files and the sizes.
 
Break On
Dim $SO
$SO=SetOption('Explicit','On')
$SO=SetOption('NoVarsInStrings','On')
$SO=SetOption('NoMacrosInStrings','On')

Dim $Dir, $Path, $Paths, $File, $Pause, $Index
$Dir = ExpandEnvironmentVars(ReadValue('HKCU\Software\Microsoft\Windows\CurrentVersion\Explorer\User Shell Folders','Desktop'))+'\Test'

$Index = 0
For Each $File In DirPlus($Dir,"/s /f mp3 mp4 mov avi mpg mpeg wmv asx divx mov jpg gif ")
$Path = Left($File.Path, InStrRev($File.Path,"\"))
If -1 = AScan($Paths,$Path)
ReDim Preserve $Paths[UBound($Paths)+1]
$Paths[UBound($Paths)] = $Path
EndIf
$Index=$Index+1
''+$Index +': ' +$File + ' ' + $File.Size ?
Next

'Press anykey to continue...' ?
Get $Pause

Function DirPlus($path,optional $Options, optional $f, optional $sfflag)
If not vartype($f) DIM $f EndIf
If not vartype($sfflag) DIM $sfflag EndIf

DIM $file, $i, $temp, $item, $ex1, $mask,$mask1,$maskArray,$maskarray1,
$ex2, $code, $CodeWeight, $targetWeight, $weight, $masktrue
DIM $tarray[0]

$ex1 = SetOption(Explicit,on)
$ex2 = SetOption(NoVarsInStrings,on)
$codeWeight = 0

If not Exist($path)
$temp = SetOption(Explicit,$ex1)
$temp = SetOption(NoVarsInStrings,$ex2)
Exit @ERROR
EndIf

If not vartype($f)
$f = CreateObject("Scripting.FileSystemObject").getfolder($path)
EndIf
If @ERROR
$temp = SetOption(Explicit,$ex1)
$temp = SetOption(NoVarsInStrings,$ex2)
Exit @ERROR
EndIf

For Each $temp In Split($options,"/")
$temp=Trim($temp)
Select
Case left($temp,1) = "s"
If not vartype($sfflag)
If Val(right($temp,-1)) = 0
$sfflag = -1
Else
$sfflag = Val(right($temp,-1))
EndIf
EndIf
Case Left($temp,1) = "a"
Select
Case Right($temp,-1)="d"
$codeWeight = $codeWeight + 1
$temp = "if $file.attributes & 16 " ;"if $file.type = 'File Folder' "
Case Right($temp,-1)="-d"
$codeWeight = $codeWeight + 1
$temp = "if ($file.attributes & 16)=0 " ;"if $file.type <> 'File Folder' "
Case Right($temp,-1)="s"
$codeWeight = $codeWeight + 1
$temp = "if $file.attributes & 4 "
Case Right($temp,-1)="-s"
$codeWeight = $codeWeight + 1
$temp = "if ($file.attributes & 4)=0 "
Case Right($temp,-1)="h"
$codeWeight = $codeWeight + 1
$temp = "if $file.attributes & 2 "
Case Right($temp,-1)="-h"
$codeWeight = $codeWeight + 1
$temp = "if ($file.attributes & 2)=0 "
Case Right($temp,-1)="r"
$codeWeight = $codeWeight + 1
$temp = "if $file.attributes & 1 "
Case Right($temp,-1)="-r"
$codeWeight = $codeWeight + 1
$temp = "if ($file.attributes & 1)=0 "
Case Right($temp,-1)="a"
$codeWeight = $codeWeight + 1
$temp = "if $file.attributes & 32 "
Case Right($temp,-1)="-a"
$codeWeight = $codeWeight + 1
$temp = "if ($file.attributes & 32)=0 "
EndSelect
$code = $temp + "$weight=$weight+1 endif" +@CRLF + $code

Case Left($temp,1) = "m"
$maskarray = Split(Right($temp,-2),"|")
$codeweight = $codeweight + 1
$code = "$masktrue=0 for Each $mask in $maskarray if instr($file.name,$mask) $masktrue=1 " +
"EndIf Next If $masktrue $weight=$weight+1 endif" + @CRLF +$code
Case Left($temp,1) = "f"
$maskarray1 = Split(Right($temp,-2)," ")
$codeweight = $codeweight + 1
$code = "$masktrue=0 for Each $mask1 in $maskarray1 if substr($file.name,Instrrev($file.name,'.')+1)" +
"=$mask1 $masktrue=1 EndIf Next If $masktrue $weight=$weight+1 endif" + @CRLF +$code

EndSelect
Next
$code = "$weight = 0 $targetWeight = " + $codeweight + @CRLF + $code
$code = $code + "if $weight = $targetweight Exit 1 endif"

For Each $file In $f.subfolders
If Execute($code)
$tarray[$i] = $file
$i = $i + 1
ReDIM preserve $tarray[$i]
EndIf
If $sfflag
$temp = dirplus($file,$options,$file,$sfflag-1)
For Each $item In $temp
$tarray[$i] = $item
$i = $i + 1
ReDIM preserve $tarray[$i]
Next
EndIf
Next
For Each $file In $f.files
If Execute($code)
$tarray[$i] = $file
$i = $i + 1

ReDIM preserve $tarray[$i]
EndIf
Next

If $i
ReDIM preserve $tarray[$i-1]
$i=0
Else
$tarray = 0
EndIf

$dirplus = $tarray
$temp = SetOption(Explicit,$ex1)
$temp = SetOption(NoVarsInStrings,$ex2)
Exit @ERROR
EndFunction