KB Issue
Using the ExifLib.dll on a website without a reference to the DLL library, you will receive Type 'ExifReader' is not defined.
Issue Details
When using Visual Studio, you add a reference to the ExifLib.dll
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, which will add files to the /bin folder within your website directory. You can then make references to the Library using simple code like this.
Code supplied by Snarf0001.
[ASP.NET - Add a reference to the ExifLib.dll]
CFFCS | CarrzSynEdit: | ASP.NET (VB/C#) 
Dim make As String
        Dim model As String

        Using exReader As New ExifReader(fileName)
            exReader.GetTagValue(Of String)(ExifTags.Make, make)
            exReader.GetTagValue(Of String)(ExifTags.Model, model)
        End Using

        lblMake.Text = make
        lblModel.Text = model

Recreate Issue
Using the code above that works within Visual Studio does not work in a website without referencing the DLL file within your project.
Resolve Issue
Dated: June 24, 2026
The Microsoft Blog post no longer exist. Link kept here for Historical Purposes.

This is taken from the blogs over at Microsoft. Thanks to their Blog Member. https://blogs.msdn.microsoft.com/tolong/author/tolong/ for this information.
Using the Visual Basic Developer Command Prompt.
  1. Click on your [Start] Menu.
  2. Choose [Programs]
  3. Scroll down to the [Visual Studio 2015] (your Version number here)
  4. Choose [Developer Command Prompt for VS2015] (your Version number here)
When the window opens, do the following commands.
[CMD/Linux - Browsing to Directoy]
CFFCS | CarrzSynEdit: | CMD (Windows Command Prompt) | L (Linux) 
C:\Windows\system32>
::type in
cd G:\ (Replacing the G with the drive you have your DLL files on)
G:\>
::Type in cd Packages (To in the rest of the location here, and hit Enter)
G:\Packages>
::NEXT
G:\Packages>gacutil -i ExifLib.dll

If successful, you will receive this message.
[CMD/Linux - .NET Global Assembly Cache Utility]
CFFCS | CarrzSynEdit: | CMD (Windows Command Prompt) | L (Linux) 
Microsoft (R) .NET Global Assembly Cache Utility.  Version 4.0.30319.0
Copyright (c) Microsoft Corporation.  All rights reserved.

Assembly successfully added to the cache


NEXT
G:\Packages>gacutil -l ExifLib
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If successful, you will receive this message.
[CMD/Linux - .NET Global Assembly Cache Utility.]
CFFCS | CarrzSynEdit: | CMD (Windows Command Prompt) | L (Linux) 
Microsoft (R) .NET Global Assembly Cache Utility.  Version 4.0.30319.0
Copyright (c) Microsoft Corporation.  All rights reserved.

The Global Assembly Cache contains the following assemblies:
  ExifLib, =1.7.0.0, =neutral, =30284005913968db, =MSIL

Number of  = 1

The above string you will need.
ExifLib, Version=1.7.0.0, Culture=neutral, PublicKeyToken=30284005913968db, processorArchitecture=MSIL
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Now, with the above done, you will need to add that information into your web.config
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file.
Which will look like this.
[ASP.NET - web.config]
CFFCS | CarrzSynEdit: | ASP.NET (VB/C#) 
<?xml version="1.0"?>
<configuration>
  <system.web>
    <compilation debug="true" strict="false" explicit="true" targetFramework="4.5">
      <assemblies>
        <add assembly="ExifLib, Version=1.7.0.0, Culture=neutral, PublicKeyToken=30284005913968db, processorArchitecture=MSIL"/>
      </assemblies>
    </compilation>
  </system.web>
</configuration>

You will then be able to run your ExifLib
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website on your server.
how-to-get-your-publickeytoken«
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