This PowerShell script is used shrink the windows image before SysPrep by removing volume caches, update backups and update caches.

Clean-ImageBeforeSysPrep.ps1

<#
*********************************************************************************************************
* Requires          | Requires PowerShell 3.0                                                           *
* ===================================================================================================== *
* Modified by       |    Date    | Revision | Comments                                                  *
* _____________________________________________________________________________________________________ *
* Ioan Popovici     | 2017-07-10 | v1.0     | First version                                             *
* Ioan Popovici     | 2017-07-10 | v2.0     | Vastly improved                                           *
* Ioan Popovici     | 2017-07-14 | v2.1     | Bug fixes and improvements                                *
* Andrew Reiter     | 2017-09-07 | v2.2     | Fix Copy-Item Bug                                         *
* Ioan Popovici     | 2018-05-24 | v2.3     | Fix Windows 10 1803 bigger image after cleanup            *
* ===================================================================================================== *
*                                                                                                       *
*********************************************************************************************************

.SYNOPSIS
    This PowerShell script is used shrink the image before SysPrep.
.DESCRIPTION
    This PowerShell script is used shrink the image before SysPrep by removing volume caches, update backups and update caches.
.EXAMPLE
    C:\Windows\System32\WindowsPowerShell\v1.0\PowerShell.exe -NoExit -NoProfile -File Clean-ImageBeforeSysPrep.ps1
.NOTES
    Credit for the original VBScript to: @mikael_nystrom https://deploymentbunny.com
.NOTES
    To do:
    * Add error handling.
    * Add better logging.
.LINK
    https://sccm-zone.com
    https://github.com/JhonnyTerminus/SCCM
#>

##*=============================================
##* VARIABLE DECLARATION
##*=============================================
#region VariableDeclaration

## Variables: Get Machine Operating System
[String]$RegExPattern =  '(Windows\ (?:7|8\.1|8|10|Server\ (?:2008\ R2|2012\ R2|2012|2016)))'
[String]$MachineOS = (Get-WmiObject -Class Win32_OperatingSystem -ComputerName $Env:ComputerName | Select-Object Caption | `
    Select-String -AllMatches -Pattern $RegExPattern | Select-Object -ExpandProperty Matches).Value
## Variables: Get Volume Caches registry paths
[String]$regVolumeCachesRootPath = 'HKLM:SOFTWARE\Microsoft\Windows\CurrentVersion\Explorer\VolumeCaches'
[Array]$regVolumeCachesPaths = Get-ChildItem -Path $regVolumeCachesRootPath | Select-Object -ExpandProperty Name
## Variables: CleanMgr cleanup settings
[String]$regSageSet = '5432'
[String]$regName = 'StateFlags'+$regSageSet
[String]$regValue = '00000002'
[String]$regType = 'DWORD'

#endregion
##*=============================================
##* END VARIABLE DECLARATION
##*=============================================

##*=============================================
##* FUNCTION LISTINGS
##*=============================================
#region FunctionListings

#region Function Start-Cleanup
Function Start-Cleanup {
<#
.SYNOPSIS
    Cleans volume caches, update backups and update caches.
.DESCRIPTION
    Cleans volume caches, update backups and update caches depending on the selected options.
.PARAMETER CleanupOptions
    The CleanupOptions depending of what type of cleanup to perform.
.EXAMPLE
    Start-Cleanup -CleanupOptions ('comCacheRepair','comCacheCleanup','updCacheCleanup','volCacheCleanup')
.NOTES
    This is an internal script function and should typically not be called directly.
.LINK
    https://sccm-zone.com
    https://github.com/JhonnyTerminus/SCCM
#>
    Param (
        [Parameter(Mandatory=$true,Position=0)]
        [Alias('cOptions')]
        [Array]$CleanupOptions
    )

    Write-Host "$MachineOS Detected. Starting Cleanup... `n" -ForegroundColor 'Yellow' -BackgroundColor 'Black'
    ## Perform Cleanup Actions
    Switch ($CleanupOptions) {
        'comCacheRepair' {

            #  Start Component Cache Repair
            Write-Host 'Performing Component Cache Repair...' -ForegroundColor 'Yellow' -BackgroundColor 'Black'
            Start-Process -FilePath 'DISM.exe' -ArgumentList '/Online /Cleanup-Image /RestoreHealth' -Wait
        }
        'comCacheCleanup' {

            #  Start Component Cache Cleanup
            Write-Host 'Performing Component Cache Cleanup...' -ForegroundColor 'Yellow' -BackgroundColor 'Black'
            Start-Process -FilePath 'DISM.exe' -ArgumentList '/Online /Cleanup-Image /StartComponentCleanup /ResetBase' -Wait
        }
        'volCacheCleanup' {

            #  If Volume Cache Paths exist add registry entries required by CleanMgr
            If ($regVolumeCachesPaths) {
                Write-Host "Adding $regName to the following Registry Paths:" -ForegroundColor 'Yellow' -BackgroundColor 'Black'
                $regVolumeCachesPaths | ForEach-Object {
                    Write-Host "$_"
                    New-ItemProperty -Path Registry::$_ -Name $regName -Value $regValue -PropertyType $regType -Force | Out-Null
                }

                #  If machine is Windows Server 2008 R2, copy files required by CleanMgr and wait for action to complete
                If ($MachineOS -eq 'Windows Server 2008 R2') {
                    Copy-Item -Path 'C:\Windows\winsxs\amd64_microsoft-windows-cleanmgr_31bf3856ad364e35_6.1.7600.16385_none_c9392808773cd7da\cleanmgr.exe' -Destination 'C:\Windows\System32\' -Force | Out-Null
                    Copy-Item -Path 'C:\Windows\winsxs\amd64_microsoft-windows-cleanmgr.resources_31bf3856ad364e35_6.1.7600.16385_en-us_b9cb6194b257cc63\cleanmgr.exe.mui' -Destination 'C:\Windows\System32\en-US\' -Force | Out-Null
                }

                #  Start Volume Cache Cleanup
                Write-Host 'Performing Volume Cache Cleanup...' -ForegroundColor 'Yellow' -BackgroundColor 'Black'
                Start-Process -FilePath 'CleanMgr.exe' -ArgumentList "/sagerun:$regSageSet" -Wait
            }
            Else {
                Write-Host 'Path Not Found! Skipping...' -ForegroundColor 'Red' -BackgroundColor 'Black'
            }
        }
        'volShadowCleanup' {

            #  Start Volume Cache Cleanup
            Write-Host 'Performing Volume Shadow Cleanup...' -ForegroundColor 'Yellow' -BackgroundColor 'Black'
            Start-Process -FilePath 'vssadmin.exe' -ArgumentList 'Delete Shadows /All' -Wait
        }
        'updCacheCleanup' {

            #  Start Update Cache Cleanup
            Write-Host 'Performing Update Cache Cleanup...' -ForegroundColor 'Yellow' -BackgroundColor 'Black'
            Stop-Service -Name 'wuauserv' | Out-Null
            Remove-Item -Path 'C:\Windows\SoftwareDistribution\' -Recurse -Force | Out-Null
            Start-Service -Name 'wuauserv'
        }
    }
}

#endregion

#endregion
##*=============================================
##* END FUNCTION LISTINGS
##*=============================================

##*=============================================
##* SCRIPT BODY
##*=============================================
#region ScriptBody

## Perform different cleanup actions depending on the detected Operating System, the action order is intentional
If ($MachineOS) {
    Switch ($MachineOS) {
        'Windows 7' {
            Start-Cleanup ('volCacheCleanup','updCacheCleanup')
        }
        'Windows 8' {
            Start-Cleanup ('comCacheRepair','comCacheCleanup','volCacheCleanup','updCacheCleanup')
        }
        'Windows 8.1' {
            Start-Cleanup ('comCacheRepair','comCacheCleanup','volCacheCleanup','updCacheCleanup')
        }
        'Windows 10' {
            Start-Cleanup ('comCacheRepair','volCacheCleanup','updCacheCleanup','comCacheCleanup','volShadowCleanup')
        }
        'Windows Server 2008 R2' {
            Start-Cleanup ('volCacheCleanup','updCacheCleanup')
        }
        'Windows Server 2012' {
            Start-Cleanup ('comCacheRepair','comCacheCleanup','updCacheCleanup')
        }
        'Windows Server 2012 R2' {
            Start-Cleanup ('comCacheRepair','comCacheCleanup','updCacheCleanup')
        }
        'Windows Server 2016' {
            Start-Cleanup ('updCacheCleanup','comCacheCleanup')
        }
        Default {
            Write-Host "Unknown Operating System, Skipping Cleanup! `n" -ForegroundColor 'Red' -BackgroundColor 'Black'
        }
    }
}
Else {
    Write-Host "Unknown Operating System, Skipping Cleanup! `n" -ForegroundColor 'Red' -BackgroundColor 'Black'
}

#endregion
##*=============================================
##* END SCRIPT BODY
##*=============================================