PowerShell script to sequentially rename image files (.jpg, .png, .webp) in the current directory using a configurable prefix and index format. The script ensures all file extensions are lowercase and prevents filename collisions by checking for existing files before renaming.

README-sequential-image-renamer.md

Sequential Image Renamer (PowerShell)

Rename image files in the current directory with a sequential, zero-padded index and a customizable prefix. It supports .jpg, .png, and .webp formats, ensures lowercase file extensions, and prevents overwriting existing files by checking for filename collisions.

Features

• Sequential renaming with two-digit zero-padding (e.g., lr-demo-img-01.jpg)
• Supports .jpg, .png, .webp file types
• Automatically converts extensions to lowercase
• Avoids overwriting by skipping used filenames
• Simple and efficient—no dependencies required

Usage

1. Place the script in the folder containing the images.
2. Open PowerShell and navigate to the folder.
3. Run the script:

.\sequential-image-renamer.ps1

sequential-image-renamer.ps1

# Set starting index and naming pattern
$index = 1
$prefix = "lr-demo-img-"

# Get all .jpg, .png, and .webp files in the current folder (no subfolders)
Get-ChildItem -Path . -File | Where-Object { $_.Extension -match "\.jpg|\.png|\.webp" } | Sort-Object Name | ForEach-Object {
    # Get lowercase extension
    $extension = $_.Extension.ToLower()

    # Loop to find the next available filename
    do {
        # Format the index with leading zeros
        $formattedIndex = "{0:D2}" -f $index

        # Create the new filename
        $newName = "$prefix$formattedIndex$extension"

        # Check if the file already exists
        $exists = Test-Path -Path (Join-Path -Path $_.DirectoryName -ChildPath $newName)

        # Increment index if name exists
        if ($exists) {
            $index++
        }

    } while ($exists)

    # Perform the renaming
    Rename-Item -Path $_.FullName -NewName $newName -ErrorAction Stop

    # Increment index for next file
    $index++
}