How to Solve Image Attachment Does Not Appear Issue in Thunderbird
To solve this issue, you need to perform the following steps:
Open Thunderbird and click on the box (menu item) on the top right corner as shown below:
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Click on View > Display Inline Attachment
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You shall see the attached image inside your email (without downloading it)
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This solution does not work for PDF attachment. Only applicable to image attachment
Open Thunderbird and click on the box (menu item) on the top right corner as shown below:

Click on View > Display Inline Attachment

You shall see the attached image inside your email (without downloading it)

This solution does not work for PDF attachment. Only applicable to image attachment
Updated on: 27/02/2019
Thank you!