Unfortunately, you cannot convert the PDF file to PowerPoint without losing the quality of the picture, especially if you created the PDF file in the older versions. If you don't want to lose the picture quality is better to create a new PowerPoint presentation. If you need some unique templates instead of using the default PowerPoint design, visit this site https://okslides.com. On-site, you can find multiple great design templates, and they are all compatible with the older PowerPoint versions. I always use templates from their site because I wouldn't say I like default templates.
