If you want an image on all labels without any other text included, an easy option is to first open Excel (I’m assuming you have Excel) and save the blank/empty sheet/Workbook with a suitable name so you can recognise it, in the My Data Sources folder located in the Documents folder.
It can be saved anywhere, in a location of your choice, but you’d need to navigate to that location in the label creation procedure.
If it’s saved in the My Data Sources folder, Word will open that folder automatically for you to choose the ‘Empty’ file source (recipients) during the label creation.

Once the above has been done, open Word and click the Mailings tab > Start Mail Merge > Labels.
In the Label Options, select your label make and size.
Navigate to and insert your chosen image via the Insert > Pictures tab.
Change the ‘Wrapping’ to In front of text.
Position and resize if necessary.
Go back to the Mailings tab > Select Recipients > Use an existing list > Select the saved blank file (you need to navigate to any other location if saved there) > Click OK.
Click Address Block > OK > Update Labels > Preview Results.
Finish/Merge/Print as required.
Click the image below to see a short video of the above procedure.
I have used Word 2019 in this example. Other versions may be slightly different.



I hope the above helps you out.