File Associations

Register or unregister ImageGlass as the default photo viewer using igcmd

ImageGlass can be registered as the default photo viewer for image file formats using command-line tools. This is useful for automated installations, system configuration, and user preferences management.

set-default-viewer

Register ImageGlass as the default photo viewer for specified file extensions.

Syntax

igcmd.exe set-default-viewer [extensions] [--per-machine] [--ui]

Parameters

extensions · string · default: "all supported formats"

Semicolon-separated list of file extensions to register

Format: .ext1;.ext2;.ext3

Examples:

• .jpg;.png;.gif - Common web formats
• .jpg;.jpeg;.png;.bmp - Basic image formats
• .webp;.avif;.heic - Modern formats

If omitted, all supported image formats are registered.

--per-machine · flag

Apply registration system-wide for all users

Requires: Administrator privileges

Without this flag: Registration applies to current user only

--ui · flag

Show confirmation dialog on successful registration

Displays a user-friendly message with registration details

Exit Codes

Code	Description
0	Registration successful
1	Administrator privileges required
2	Error during registration

Examples

Register All Supported Formats

igcmd.exe set-default-viewer

Registers ImageGlass as default viewer for all supported image formats (PNG, JPG, GIF, WebP, BMP, TIFF, SVG, ICO, and more) for the current user.

Register Specific Formats

igcmd.exe set-default-viewer ".jpg;.png;.gif"

Registers only common web image formats.

System-Wide Registration

igcmd.exe set-default-viewer --per-machine

Registers for all users on the system. Requires administrator privileges.

With User Confirmation

igcmd.exe set-default-viewer ".jpg;.png" --ui

Shows a confirmation dialog after successful registration.

Complete Registration with UI

igcmd.exe set-default-viewer ".jpg;.jpeg;.png;.gif;.bmp;.webp" --per-machine --ui

Registers common formats system-wide and shows confirmation.

Common Extension Sets

Basic Image Formats

igcmd.exe set-default-viewer ".jpg;.jpeg;.png;.gif;.bmp"

Legacy and widely-supported formats.

Modern Web Formats

igcmd.exe set-default-viewer ".webp;.avif;.svg"

Next-generation web image formats.

RAW Photography Formats

igcmd.exe set-default-viewer ".cr2;.nef;.arw;.dng;.raw"

Common camera RAW formats (requires codec support).

All Common Formats

igcmd.exe set-default-viewer ".jpg;.jpeg;.png;.gif;.bmp;.tiff;.tif;.webp;.ico;.svg"

Advanced Usage

Installation Script

@echo off
echo Installing ImageGlass as default photo viewer...

rem Install for current user first
igcmd.exe set-default-viewer --ui

if %ERRORLEVEL% EQU 0 (
    echo Successfully registered for current user
) else (
    echo Failed to register
    exit /b 1
)

System Deployment Script

@echo off
rem Run with administrator privileges

echo Registering ImageGlass system-wide...
igcmd.exe set-default-viewer --per-machine

if %ERRORLEVEL% EQU 1 (
    echo Administrator privileges required
    echo Please run as administrator
    exit /b 1
)

if %ERRORLEVEL% EQU 0 (
    echo Registration successful
) else (
    echo Registration failed
    exit /b 2
)

PowerShell Registration

# Check for admin privileges
$isAdmin = ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)

if ($isAdmin) {
    Write-Host "Registering system-wide..."
    & igcmd.exe set-default-viewer --per-machine --ui
} else {
    Write-Host "Registering for current user..."
    & igcmd.exe set-default-viewer --ui
}

if ($LASTEXITCODE -eq 0) {
    Write-Host "Registration successful" -ForegroundColor Green
} else {
    Write-Host "Registration failed" -ForegroundColor Red
    exit $LASTEXITCODE
}

---

remove-default-viewer

Unregister ImageGlass as the default photo viewer for specified file extensions.

Syntax

igcmd.exe remove-default-viewer [extensions] [--per-machine] [--ui]

Parameters

extensions · string · default: "all registered formats"

Semicolon-separated list of file extensions to unregister

Format: .ext1;.ext2;.ext3

If omitted, all registered formats are unregistered.

--per-machine · flag

Remove system-wide registration for all users

Requires: Administrator privileges

--ui · flag

Show confirmation dialog on successful removal

Exit Codes

Code	Description
0	Unregistration successful
1	Administrator privileges required
2	Error during unregistration

Examples

Remove All Associations

igcmd.exe remove-default-viewer

Removes ImageGlass as default viewer for all registered formats.

Remove Specific Formats

igcmd.exe remove-default-viewer ".jpg;.png"

Removes only specified format associations.

System-Wide Removal

igcmd.exe remove-default-viewer --per-machine

Removes system-wide associations. Requires administrator privileges.

With Confirmation Dialog

igcmd.exe remove-default-viewer --ui

Shows confirmation after removal.

Advanced Usage

Uninstall Script

@echo off
echo Removing ImageGlass file associations...

igcmd.exe remove-default-viewer --ui

if %ERRORLEVEL% EQU 0 (
    echo Associations removed successfully
) else (
    echo Failed to remove associations
)

Clean Removal Script

@echo off
rem Remove user and system associations

echo Removing user associations...
igcmd.exe remove-default-viewer

if %ERRORLEVEL% EQU 0 (
    echo User associations removed
)

echo Removing system associations...
igcmd.exe remove-default-viewer --per-machine

if %ERRORLEVEL% EQU 1 (
    echo System removal requires administrator privileges
) else if %ERRORLEVEL% EQU 0 (
    echo System associations removed
)

PowerShell Removal

Write-Host "Removing ImageGlass associations..."

& igcmd.exe remove-default-viewer --ui

if ($LASTEXITCODE -eq 0) {
    Write-Host "Successfully removed associations" -ForegroundColor Green
} elseif ($LASTEXITCODE -eq 1) {
    Write-Host "Administrator privileges required" -ForegroundColor Yellow
} else {
    Write-Host "Failed to remove associations" -ForegroundColor Red
}

---

Understanding File Associations

Per-User vs Per-Machine

Per-User Registration (Default)

igcmd.exe set-default-viewer

• Applies to current user only
• No administrator privileges required
• Stored in HKEY_CURRENT_USER registry
• Does not affect other users
• Preferred for personal installations

Per-Machine Registration

igcmd.exe set-default-viewer --per-machine

• Applies to all users on the system
• Requires administrator privileges
• Stored in HKEY_LOCAL_MACHINE registry
• Affects all user accounts
• Preferred for enterprise deployments

Supported Image Formats

When registering without specifying extensions, ImageGlass registers for all supported formats:

• Raster: JPG, PNG, GIF, BMP, TIFF, WebP, AVIF, HEIC, HEIF
• Vector: SVG
• Icons: ICO, CUR
• RAW: CR2, NEF, ARW, DNG, RAF, ORF (with codecs)
• Other: TGA, PCX, PSD (preview)

Windows Default Apps

After registration:

• ImageGlass appears in Windows “Default apps” settings
• Users can still manually change associations in Settings
• Registration creates the necessary registry entries
• Does not override user’s explicit manual choices

Deployment Scenarios

Silent Installation

@echo off
rem Silent installation with file associations

msiexec /i ImageGlass.msi /quiet
igcmd.exe set-default-viewer --per-machine
exit /b %ERRORLEVEL%

Interactive Installation

@echo off
echo Installing ImageGlass...
msiexec /i ImageGlass.msi /qb

echo.
echo Would you like to set ImageGlass as default photo viewer? (Y/N)
set /p choice="Your choice: "

if /i "%choice%"=="Y" (
    igcmd.exe set-default-viewer --ui
)

Enterprise Group Policy Script

@echo off
rem GPO startup script for IT deployment

rem Check if ImageGlass is installed
if not exist "C:\Program Files\ImageGlass\igcmd.exe" (
    echo ImageGlass not installed
    exit /b 1
)

rem Register system-wide
"C:\Program Files\ImageGlass\igcmd.exe" set-default-viewer --per-machine

if %ERRORLEVEL% EQU 0 (
    echo ImageGlass registered successfully
) else (
    echo Failed to register ImageGlass
    exit /b 1
)

PowerShell Deployment

# Enterprise deployment script

function Install-ImageGlassAssociations {
    param(
        [string]$Scope = "CurrentUser"
    )
    
    $igcmdPath = "C:\Program Files\ImageGlass\igcmd.exe"
    
    if (-not (Test-Path $igcmdPath)) {
        Write-Error "ImageGlass not found at $igcmdPath"
        return $false
    }
    
    $arguments = @("set-default-viewer")
    
    if ($Scope -eq "AllUsers") {
        $arguments += "--per-machine"
    }
    
    $result = Start-Process -FilePath $igcmdPath -ArgumentList $arguments -Wait -PassThru -NoNewWindow
    
    return ($result.ExitCode -eq 0)
}

# Usage
if (Install-ImageGlassAssociations -Scope "AllUsers") {
    Write-Host "Successfully registered ImageGlass" -ForegroundColor Green
} else {
    Write-Host "Failed to register ImageGlass" -ForegroundColor Red
}

Error Handling

Comprehensive Error Handling

@echo off
setlocal

set "extensions=.jpg;.png;.gif"

echo Registering ImageGlass for: %extensions%
igcmd.exe set-default-viewer "%extensions%" --ui

if %ERRORLEVEL% EQU 0 (
    echo Registration successful
    exit /b 0
)

if %ERRORLEVEL% EQU 1 (
    echo.
    echo Administrator privileges required.
    echo Please run this script as administrator.
    echo.
    pause
    exit /b 1
)

if %ERRORLEVEL% EQU 2 (
    echo.
    echo An error occurred during registration.
    echo Please check that ImageGlass is properly installed.
    echo.
    pause
    exit /b 2
)

echo Unknown error
exit /b %ERRORLEVEL%

PowerShell Error Handling

try {
    $extensions = ".jpg;.png;.gif;.webp"
    
    Write-Host "Registering file associations: $extensions"
    
    $process = Start-Process -FilePath "igcmd.exe" `
        -ArgumentList "set-default-viewer", $extensions, "--ui" `
        -Wait -PassThru -NoNewWindow
    
    switch ($process.ExitCode) {
        0 {
            Write-Host "Registration successful" -ForegroundColor Green
        }
        1 {
            Write-Warning "Administrator privileges required"
            
            # Prompt to elevate
            $elevated = Start-Process -FilePath "igcmd.exe" `
                -ArgumentList "set-default-viewer", $extensions, "--ui", "--per-machine" `
                -Verb RunAs -Wait -PassThru
            
            if ($elevated.ExitCode -eq 0) {
                Write-Host "Registration successful (elevated)" -ForegroundColor Green
            }
        }
        2 {
            Write-Error "Registration failed. Check ImageGlass installation."
        }
        default {
            Write-Error "Unknown error occurred (exit code: $($process.ExitCode))"
        }
    }
} catch {
    Write-Error "Exception occurred: $_"
}

Testing Associations

Verify Registration

# Check if ImageGlass is registered for a specific extension
function Test-ImageGlassAssociation {
    param([string]$Extension)
    
    $key = "HKCU:\Software\Classes\$Extension"
    
    if (Test-Path $key) {
        $value = Get-ItemProperty -Path $key -Name "(Default)" -ErrorAction SilentlyContinue
        
        if ($value -and $value."(Default)" -match "ImageGlass") {
            Write-Host "$Extension is associated with ImageGlass" -ForegroundColor Green
            return $true
        }
    }
    
    Write-Host "$Extension is NOT associated with ImageGlass" -ForegroundColor Red
    return $false
}

# Test common formats
@(".jpg", ".png", ".gif", ".webp") | ForEach-Object {
    Test-ImageGlassAssociation $_
}

See Also

• CLI Overview
• All Commands
• Quick Setup
• Set Wallpaper