Great suggestion, only in my case the contrast of the signatures to the backgrounds is not good, and this would be a problem with many works saved by Google as

Great suggestion, only in my case the contrast of the signatures to the backgrounds is not good, and this would be a problem with many works saved by Google as well. But it does give me the thought implementing this idea might be technically easier than I thought. Implement the saved signatures as images with the background whited-out and provide tools to easily bring a requested signature image into that state.