Powershell to create html galleries with thumbnails of images and videos in a folder

This script is designed to be placed in a folder with lots of images including subfolders, create thumbnails of all the images found then add 100 per HTML page with a "Next" link at the bottom linking to the next gallery page.

Make sure to adjust the settings in the config section to suit your needs.

See screenshots for examples.

Script

##############
# Config
##############

# Image file extensions
    $imagefileext = @('.jpg','.png')

# Video file extensions
    $videofileext = @('.avi','.mp4')

# Folder where pics are located
    $imagefolder ="pics\" 

# Number of images per gallery.html
    $newfileevery = "100"

# Gallery filename
    $filenameout = "Gallery"

# Thumbnail folder
    $thumbnaildir = "Thumbnails"

# Create image limit number for next link
    $imagelimit = $newfileevery -1

# Style
$css = @' 
<style>
    body
  {
      font-family: Arial; 
      background-color: Gainsboro;
  }

    table, th, td{
      border: 1px solid;
    }

    h1{
        background-color:Tomato;
        color:white;
        text-align: center;
    }
</style>
'@ 

##############
# End config
##############

# Check if pics folder is present
    if (Test-Path -Path $imagefolder) {
        "Thumbnail folder present"
    } else {
           Write-Host "No $imagefolder folder present"
           break
    }

# Create thumbnails folder
    if (Test-Path -Path $thumbnaildir) {
        "Thumbnail folder present"
    } else {
           New-Item -Name $thumbnaildir -ItemType "directory"
    }

# Grab all files in pics, sort and store in array
    $items = get-childitem -File $imagefolder -recurse | Sort-Object Name | % { $_.FullName } 
    $arrayIndex = 0
    $fileIndex = 0

# Set nextpage number
    $fileIndexnext = 1

# Begin loop
    foreach ($i in $items) {
        if ($arrayIndex%$newfileevery -eq 0) 
        {
            $fileIndex++
            $filename = "$filenameout$('{0:d5}' -f $fileIndex).html"  
            add-Content -Path $filename -Value "$css"
        }

# Split path for thumbnail folder
    $thumbnailsplit = Split-Path (Split-Path $i -Parent) -Leaf

# Get file extension of current file
$extn = [IO.Path]::GetExtension($i)

# If file extension matches one in the image extension arry do this
    if ($extn -in $imagefileext )
    {

# Create thumbnails
    $full = [System.Drawing.Image]::FromFile($i);
    $thumb = $full.GetThumbnailImage(250, 300, $null, [intptr]::Zero);
    $thumb.Save("$i.thumb.jpg");
    $full.Dispose();
    $thumb.Dispose();
    $thumbfile = $i + '.thumb.jpg'

# Create thumbnail subfolder
    $thumbnaildir2 = $thumbnaildir + '\' + $thumbnailsplit + '\'
    
# Create thumbnail subfolders
    if (Test-Path -Path $thumbnaildir2) {
        "Thumbnail folder present"
    } else {
           New-Item -Name $thumbnaildir2 -ItemType "directory"
    }
   
# Move thumbnail to thumbnail folder
    Move-Item -Path $thumbfile -Destination $thumbnaildir2

# Split filename from array and create new file path for thumbnail
    $finalthumb = Split-Path $i -leaf
    $finalthumb2 = $thumbnaildir2 + $finalthumb +'.thumb.jpg'

# Add thumbnail and link to full size image to html file
    add-Content -Path $filename -Value "<a href='$i'><img src='$finalthumb2' height='250' width='300' alt='$i'></a>"

# If image reaches limit per page create next gallery link
    if ($arrayIndex%$newfileevery -eq $imagelimit) {
        $fileIndexnext++
        $filename2 = "$filenameout$('{0:d5}' -f $fileIndexnext).html"
        add-Content -Path $filename -Value "<br><center><a href='$filename2'>Next</a></center>"    
    }

# Else if file extension doesnt match any in image array check it against video extension array and do       
    } elseif ($extn -in $videofileext){

    $thumbfile = $i + '.thumb.jpg'
    ffmpeg -ss 00:00:10 -i $i -frames 1 -vf '"select=not(mod(n\,1000)),scale=320:240,tile=2x3"' $thumbfile

# Create thumbnail subfolder
    $thumbnaildir2 = $thumbnaildir + '\' + $thumbnailsplit + '\'
   
# Create thumbnail subfolders
    if (Test-Path -Path $thumbnaildir2) {
        "Thumbnail folder present"
    } else {
           New-Item -Name $thumbnaildir2 -ItemType "directory"
    }
   
# Move thumbnail to thumbnail folder
    Move-Item -Path $thumbfile -Destination $thumbnaildir2

# Split filename from array and create new file path for thumbnail
    $finalthumb = Split-Path $i -leaf
    $finalthumb2 = $thumbnaildir2 + $finalthumb +'.thumb.jpg'

# Add thumbnail and link to full size image to html file
    add-Content -Path $filename -Value "<a href='$i'><img src='$finalthumb2' height='250' width='300' alt='$i'></a>"

# If image reaches limit per page create next gallery link
    if ($arrayIndex%$newfileevery -eq $imagelimit) {
        $fileIndexnext++
        $filename2 = "$filenameout$('{0:d5}' -f $fileIndexnext).html"
        add-Content -Path $filename -Value "<br><center><a href='$filename2'>Next</a></center>"    
    }


} 

# Increase array count
    $arrayIndex++

}