Powershell-Script for renaming (image)files to creation-date

Rename3000_v2.0.ps1

#
# ===================================================================
#                             RENAME 3000
# ===================================================================
# Purpose:           Rename every file with extension $extension (Line 21) with EXIF-Date or CreationDate
#                    Append "(1)", "(2)", etc. for already-existent files
#                    Keeping old filename, if new one is the same
#
# Author:            Levin Baumann
# ===================================================================
#
$nocomment = [reflection.assembly]::LoadWithPartialName("System.Drawing")
$count = 0

[string] $extension = ".jpg"
$filecount = (Get-ChildItem ("*"+$extension) | Measure-Object).Count;

Write-Host "INFO:" -ForegroundColor Black -BackgroundColor Blue -NoNewline
Write-Host "Do you really want to rename" -ForegroundColor Blue -BackgroundColor White -NoNewline
Write-Host (" " + $filecount + " ") -ForegroundColor Blue -NoNewline
Write-Host "file(s) of type" -ForegroundColor Blue -BackgroundColor White -NoNewline
Write-Host (" " + $extension + " ") -ForegroundColor Blue -NoNewline
Write-Host "?" -ForegroundColor Blue -BackgroundColor White
Write-Host "Press any key to continue..."
$null = $Host.UI.RawUI.ReadKey('NoEcho,IncludeKeyDown')

get-childitem ("*"+$extension) | foreach {
	$count++
	$failed = 0
	$NewNameIsOldName = 0
	try {
		$pic = New-Object System.Drawing.Bitmap($_.Name)
		$bitearr = $pic.GetPropertyItem(36867).Value
		$string = [System.Text.Encoding]::ASCII.GetString($bitearr)
		$date = [datetime]::ParseExact($string,"yyyy:MM:dd HH:mm:ss`0",$Null)
		[string] $newfilename = get-date $date -format yyyyMMdd_HHmmss
	}
	catch [Exception]{
		$failed = 1
	}
	
	try {
		$pic.Dispose()
	}
	catch {
		Write-Host "ERROR:" -ForegroundColor Black -BackgroundColor red -NoNewline
		Write-Host (" " + $_.Name + " ") -ForegroundColor red -NoNewline
		Write-Host "seems to be no picture." -ForegroundColor red -BackgroundColor white
	}
	
	if ($failed -eq 1) {
		Write-Host "ERROR:" -ForegroundColor Black -BackgroundColor red -NoNewline
		Write-Host "No Exif-Data for" -ForegroundColor red -BackgroundColor white -NoNewline
		Write-Host (" " + $_.Name) -ForegroundColor red
		[string] $newfilename = $_.LastWriteTime.toString("yyyyMMdd_HHmmss")
	}
	
		
	if(Test-Path ($newfilename+$extension)){
		$exists = 1
		$n = 1
		[string] $appendix = $extension
		if ($_.Name -eq ($newfilename + $appendix)) {
			$NewNameIsOldName = 1
		} else {
			while ($exists -eq 1) {
				Write-Host "WARNING:" -ForegroundColor yellow -BackgroundColor black -NoNewline
				Write-Host "Filename already exists:" -ForegroundColor black -BackgroundColor yellow -NoNewline
				Write-Host (" " + $newfilename + $appendix) -ForegroundColor yellow
			
				[string] $appendix = "(" + $n + ")"+$extension
				if (Test-Path ($newfilename + $appendix)) {
					if ($_.Name -eq ($newfilename + $appendix)) {
						$exists = 0
						$NewNameIsOldName = 1
					} else {
						$n++
					}
				} else {
					$exists = 0
				}
			}
		}
	} else {
		[string] $appendix = $extension
	}
	$newfilename += $appendix
	try {	
		if ($NewNameIsOldName -eq 0) {
			rename-item $_ $newfilename 
			Write-Host "SUCCESS:" -ForegroundColor green -BackgroundColor black -NoNewline
			Write-Host "New name for" -ForegroundColor black -BackgroundColor green -NoNewline
			Write-Host (" " + $_ + " ") -ForegroundColor green -NoNewline
			Write-Host "is" -ForegroundColor black -BackgroundColor green -NoNewline
			Write-Host (" " + $newfilename) -ForegroundColor green
		} else {
			Write-Host "INFO:" -ForegroundColor Black -BackgroundColor Blue -NoNewline
			Write-Host "Keeping old filename for" -ForegroundColor Blue -BackgroundColor White -NoNewline
			Write-Host (" " + $_) -ForegroundColor Blue
		}
	}
	catch {
		Write-Host "ERROR:" -ForegroundColor Black -BackgroundColor red -NoNewline
		Write-Host "Could not write filename" -ForegroundColor red -BackgroundColor white -NoNewline
		Write-Host (" " + $newfilename) -ForegroundColor red - NoNewline
		Write-Host "Keeping old Filename" -ForegroundColor black -BackgroundColor green -NoNewline
		Write-Host (" " + $_) -ForegroundColor green
	}
	Write-Host ("File #" + $count + "/"+$filecount)
}

Write-Host "Done. Press any key to exit..."
$null = $Host.UI.RawUI.ReadKey('NoEcho,IncludeKeyDown')

Nice. I got one for all files in a directory but it seems to not work.

Get-ChildItem *.* | %{Rename-Item $_ -NewName ('{0}{1}' -f $_.LastWriteTime.toString("yyyyMMdd-hhmmss_"), $_.Extension)}