The file formats that are mentioned in the backend can only be uploaded for logos. Apart from these, other file formats cannot be used.
Login to Backend
Go to Stores and click Configuration mentioned in Settings.
A Configuration page will be opened after clicking on Configuration option. Under, PrintXpand section, go to Product Designer Settings.
Under, Product Designer Settings, there is a section called Custom Image Upload.
The file formats selected in Allowed Extension For Upload can only be uploaded for logo images.
