Part of the reason I purchased PDFelement (Pro) was to help me process a large number of PNG files into a single PDF document. Based on the features description and even one How-To I found, I thought this was possible, but when I try to "combine files" and add my PNG files, PDFelement gives me a Failure notice for all of my files. It's possible for me to open each PNG file individually and then it's indeed opened as a PDF file, but this solution isn't really workable when I have 100s of PNGs I want to form into a single PDF. Is there some option/step that I am missing? Is there a way to do this from the command line as a batch process? (I'm running Windows 10, but I'm pretty comfortable with command line processes).