Two issues that are clear developer oversight when in the "Customize the Signature Appearance" dialog that's part of the digital signatures function:
The "Draw" option, while opening the box with the canvas, doesn't actually let you draw. Click all you want, not a single dot will appear.
The "Image" option is limited to opening .pdf files when browsing for images. Generally, one would be hoping to utilise formats such as .png, .jpg, .gif, .bmp, .tif, etc when inserting an image.
I have already tried checking for updates, repairing the install, uninstalling and reinstalling, etc.
One suggestion to simplify things would be the option to utilise the currently saved signature from "Fill and Sign".
Sorry if my tone's a bit gruff today; been wrangling government departments all day and finding myself obstructed by a broken function indicative of zero testing having been conducted on this feature before release has been the last thing I need.