SysTools DMG Viewer : Know How it Works!
Download & Install the software to read data from DMG file. The software facilitates preview of email data (EML, EMLX), Text, Images & HTML files along with the their attachments.
Open the "SysTools DMG Viewer" Application:

Click on the "Open" button to select read-only & compressed DMG file.
Select the DMG file which you want to open in the software.
Now, select the folder in which the data is present and a preview of data is generated.
Select the item which you want to open, right-click on the file and click on preview as shown:
The properties of the file such as Attachment type, Creation date, etc. will be shown under File Properties tab.
The preview of DMG file will be shown under File tab.
Attachments can be opened by double-clicking on the name of the attachment.
The preview of attachments is shown below:
The EML files are displayed as shown below:
The preview of LOG files is displayed as below:
Images can be opened using the DMG viewer software as shown in the following section:
The Hex view of the file can also be viewed under Hex tab.
The search option is provided to find files into folders by using name and extension.
Select folders >> type file extension and click on search button and all the required files will be displayed.
You can apply filters options such as date filters, etc.
To Close, Expand & Collapse all files, right-click on the selected file.