System.Drawing.Bitmap in a scheduled powershell script

Question

I've written a powershell script to date stamp multipage tiffs, but I check to make sure the file name follows the correct format before doing so. The file name must contain the date, sequence number, and number of pages. The script works fine when run manually,
but when run from task scheduler it fails to query the number of pages in the TIFF. Any ideas why the .NET features wouldn't work from a powershell script run as a scheduled task?
I am putting the page number in the variable "count" by doing the following:
 $i=[System.Drawing.Bitmap]::FromFile($file.Fullname);$i.GetFrameCount($i.FrameDimensionsList[0]) 
 $count=$i.GetFrameCount([System.Drawing.Imaging.FrameDimension]::Page)
FULL SCRIPT FOLLOWS
#Define the input and output folders and date format
$Original_TIFFs="C:\scans"
$Modified_TIFFs=";\\test\Shared\SDS\"
$date = get-date -Format d
$datename=Get-Date -format yyyyMMdd
Set-Location $Original_TIFFs
#Configure email settings
$emailFrom = "removed"
$emailTo = "removed"
$smtpServer = "removed"
$body = "Rename scanned claims file to the correct format. This email was sent from: ", $env:computername
#Define the location of the TIFF command line executable and its parameters
$200DLL='C:\TiffDLL200Commandline\Cmd200.exe '
$arg1='"FILE='
#Modify arg2 to put the output directory in front of the ; if don't want to overwrite current file
#$arg2=';|OW=Yes|BITS=2|TEXT=2;Received Date: '
$arg2=$modified_TIFFs
$arg3=';|BITS=2|TEXT=2;Received Date: '
$arg4='|TEXTOPS=-5;;10;14;"'
$files=Get-ChildItem $Original_TIFFs -Filter *.tif
if ($files -eq $null)
  $subject = "No files to process today, directory empty."
  $smtp = new-object Net.Mail.SmtpClient($smtpServer)
  $body = "No files were processed today. This email was sent from: ", $env:computername
  $smtp.Send($emailFrom, $emailTo, $subject, $body)
else
foreach ($file in $files)                                                                  
   #Begin loop to check each file and process
 #Loads subsystems for opening TIFFs and second line puts the number of images into variable
 $i=[System.Drawing.Bitmap]::FromFile($file.Fullname);$i.GetFrameCount($i.FrameDimensionsList[0]) 
 $count=$i.GetFrameCount([System.Drawing.Imaging.FrameDimension]::Page)
 #If statement checks if filename format is correct
 if ($file -match '^\d{8}\d{3}_H_S_\d+_\d{8}[.tif]{4}$')
  $file.name -match '^(?<date1>\d{8})\d{3}_H_S_(?<page_count>\d+)_(?<date2>\d{8})[.tif]{4}$'   #Regex to put tests in $matches to check against
  if (($matches.date1 -eq $datename) -and ($matches.date2 -eq $datename))                      #Check if filename contains correct date
  if ($count -eq $matches.page_count)                                                          #Check if filename
contains the correct page count
   #insert TIFF modification
    $allargs=$200Dll+$arg1+$file+$arg2+$file+$arg3+$date+$arg4
    cmd /c $allargs
    #cmd /c xcopy $file \\test\shared\SDS                                                   #Deprecated because now having
TIFF200DLL create a new file rather than overwrite
    $i.Dispose()                                                                  
            #Close file stream so file can be deleted: http://support.microsoft.com/kb/814675
    Remove-Item $file.Name
    #Next section is for a different output directory; Setup a seperate batch file to delete original TIFFs in the middle of the night
    <#
    $allargs="cmd200 "+$arg1+$file+";"+$Modified_TIFFs+";"+$arg2+$date+$arg3
    cmd /c $allargs
    #>
    else                                                                    
                 #else statement to send out error message if the number of pages differs from name
    $subject = "The number of pages in the file ", $file.FullName, "differs from the actual count of ", $count, ". File will not be sent, please correct before tomorrow for processing."
    $smtp = new-object Net.Mail.SmtpClient($smtpServer)
    $smtp.Send($emailFrom, $emailTo, $subject, $body)
  }  #Close IF/THEN for correct date is in filename
 else
    $subject = "Date portion of filename is incorrect, please fix. File will not be sent to SDS", $file.FullName," ."
    $smtp = new-object Net.Mail.SmtpClient($smtpServer)
    $smtp.Send($emailFrom, $emailTo, $subject, $body)
 }                                                    #Close IF/THEN for initial filename check
 else
    $subject = "File does not meet proper naming convention and will not be stamped nor sent to SDS", $file.FullName, " ."
    $smtp = new-object Net.Mail.SmtpClient($smtpServer)
    $smtp.Send($emailFrom, $emailTo, $subject, $body)
}                                                     #Close FOR loop
}                                                     #Close Else for check if FILES=NULL

Answer 1

You are buikding thisin the ISE?
You need too add:
add-type -AssemblyName System.Drawing
¯\_(ツ)_/¯