PicturesLandscape,landscape
PicturesBatman,batman

$picture_database_location = "$PSScriptRootpictures_database.txt"
$filter_ext = "jpg"
$rootDestination = "R:"


function determineIfFileorDirectoryExists
{    Param([string]$fileordirectory)

    <#
        Determine if a File or Directory Exists. If the file or directory doesn't exists,
        it will throw an exception.

        Args:
            string: $fileordirectory - the variable that contains the file or directory
                                       we're going to Test.

        Returns:
            None
    #>

    $fileordirectoryExists = Test-Path $fileordirectory

    if($fileordirectoryExists -eq $false){
        throw [System.IO.DirectoryNotFoundException] "Not Found: $fileordirectory"
    }
}

function determineargumentCount
{      Param([string[]]$arraytoverify)

    <#
        Determines if the array length is correct. If not, it will throw and display the elements in the array.

        Args:
            string[]: $arraytoverify - the array to check for length.

        Return:
            None
    #>

    if ($arraytoverify.Length -ne 2){
        throw "Argument count incorrect. # of Parameters: $argumentCount. `nProvided Parameters: $arraytoverify"
    }
}


try{

    # Before renaming any images we need to verify that the source location and destination exist.
    determineIfFileorDirectoryExists -fileordirectory "$picture_database_location"
    determineIfFileorDirectoryExists -fileordirectory "$rootDestination"
    $picture_database = Get-Content $picture_database_location

    ForEach ($image in $picture_database){
        # Construct an array based on the split string
        # $imagaeArray is constructed as follows:
        # $imageArray[0]: The directory that contains the images to rename
        # $imageArray[1]: The base name to rename the images
        $imageArray = $image.Split(",")
        determineargumentCount -arraytoverify $imageArray
        # Construct the Source path with USERPROFILE environment variable and the first element in the array (the directory that contains our pictures)
        $imagePath = Join-Path $env:USERPROFILE -ChildPath $imageArray[0]
        determineIfFileorDirectoryExists -fileordirectory "$imagePath"
        Set-Location -Path "$imagePath"
        # Filter images by type and bulid a list with all the image names
        $fileList = (Get-ChildItem $imagePath -Filter "*.jpg").Name

        if($fileList.Length -gt 0){

            # Construct a string representing the desination path
            $DestinationPath = Join-Path $rootDestination -ChildPath $imageArray[0]
            $doesDirectoryExist = Test-Path $DestinationPath

            if($doesDirectoryExist -eq $false){
                # - ErrorAction Stop - stops the script if the action take fails.
                md "$DestinationPath" -ErrorAction Stop
                determineIfFileorDirectoryExists -fileordirectory "$DestinationPath"
            }

            # Get the number of pictures in the destionation and set the counter.
            [int]$fileCounter = (Get-ChildItem $DestinationPath -Filter "*.jpg").Length
            ForEach ($imagetoRename in $fileList){
                $fileCounter++
                $renamed_file = "{0}_{1}.{2}" -f $imageArray[1],$fileCounter,$filter_ext
                $imageDestination = Join-Path $DestinationPath -ChildPath $renamed_file
                Write-Output "Image : {0} will be renamed to {1}" -f $imagetoRename, $imageDestination
                Move-Item -Path "$imagetoRename" -Destination "$imageDestination"
            }

        }
   }
   Set-Location $PSScriptRoot
}

catch [System.IO.DirectoryNotFoundException]
{
    Write-Output $PSItem.Exception.Message
}

catch [System.IO.IOException]
{
    Write-Output $PSItem.Exception.Message
}

catch{
    Write-Output $PSItem.Exception.Message
}

finally{

    exit
}

landscape_1.jpg
landscape_2.jpg

batman_1.jpg
batman_2.jpg