Why won't my signature image show?

In Acrobat Reader DC I'm trying to setup a Digital ID with an image of a handwritten signature. I have a png and a jpg image of said signature which I want to import. When I go to Tool->Preferences->Signatures->Creation and Appearance->More I can find the method to make a signature just fine. The same goes for making a Digital ID certificate. However, when I try to add the image nothing but the additional text is shown in the preview, nor when I add the signature to the document. Please see the image below.

Anyone know what's going on?