> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/d2phap/ImageGlass/llms.txt
> Use this file to discover all available pages before exploring further.

# 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

```bash theme={null}
igcmd.exe set-default-viewer [extensions] [--per-machine] [--ui]
```

### Parameters

<ParamField path="extensions" type="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.
</ParamField>

<ParamField path="--per-machine" type="flag">
  Apply registration system-wide for all users

  **Requires:** Administrator privileges

  **Without this flag:** Registration applies to current user only
</ParamField>

<ParamField path="--ui" type="flag">
  Show confirmation dialog on successful registration

  Displays a user-friendly message with registration details
</ParamField>

### Exit Codes

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

### Examples

#### Register All Supported Formats

```bash theme={null}
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

```bash theme={null}
igcmd.exe set-default-viewer ".jpg;.png;.gif"
```

Registers only common web image formats.

#### System-Wide Registration

```bash theme={null}
igcmd.exe set-default-viewer --per-machine
```

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

#### With User Confirmation

```bash theme={null}
igcmd.exe set-default-viewer ".jpg;.png" --ui
```

Shows a confirmation dialog after successful registration.

#### Complete Registration with UI

```bash theme={null}
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

```bash theme={null}
igcmd.exe set-default-viewer ".jpg;.jpeg;.png;.gif;.bmp"
```

Legacy and widely-supported formats.

#### Modern Web Formats

```bash theme={null}
igcmd.exe set-default-viewer ".webp;.avif;.svg"
```

Next-generation web image formats.

#### RAW Photography Formats

```bash theme={null}
igcmd.exe set-default-viewer ".cr2;.nef;.arw;.dng;.raw"
```

Common camera RAW formats (requires codec support).

#### All Common Formats

```bash theme={null}
igcmd.exe set-default-viewer ".jpg;.jpeg;.png;.gif;.bmp;.tiff;.tif;.webp;.ico;.svg"
```

### Advanced Usage

#### Installation Script

```bash theme={null}
@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

```bash theme={null}
@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

```powershell theme={null}
# 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

```bash theme={null}
igcmd.exe remove-default-viewer [extensions] [--per-machine] [--ui]
```

### Parameters

<ParamField path="extensions" type="string" default="all registered formats">
  Semicolon-separated list of file extensions to unregister

  **Format:** `.ext1;.ext2;.ext3`

  If omitted, all registered formats are unregistered.
</ParamField>

<ParamField path="--per-machine" type="flag">
  Remove system-wide registration for all users

  **Requires:** Administrator privileges
</ParamField>

<ParamField path="--ui" type="flag">
  Show confirmation dialog on successful removal
</ParamField>

### Exit Codes

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

### Examples

#### Remove All Associations

```bash theme={null}
igcmd.exe remove-default-viewer
```

Removes ImageGlass as default viewer for all registered formats.

#### Remove Specific Formats

```bash theme={null}
igcmd.exe remove-default-viewer ".jpg;.png"
```

Removes only specified format associations.

#### System-Wide Removal

```bash theme={null}
igcmd.exe remove-default-viewer --per-machine
```

Removes system-wide associations. Requires administrator privileges.

#### With Confirmation Dialog

```bash theme={null}
igcmd.exe remove-default-viewer --ui
```

Shows confirmation after removal.

### Advanced Usage

#### Uninstall Script

```bash theme={null}
@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

```bash theme={null}
@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

```powershell theme={null}
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)

```bash theme={null}
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

```bash theme={null}
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

```bash theme={null}
@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

```bash theme={null}
@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

```bash theme={null}
@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

```powershell theme={null}
# 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

```bash theme={null}
@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

```powershell theme={null}
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

```powershell theme={null}
# 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](/cli/overview)
* [All Commands](/cli/igcmd-commands)
* [Quick Setup](/cli/quick-setup)
* [Set Wallpaper](/cli/set-wallpaper)