Hi @Stuart_Whitaker, please note that the Knowledge Base article you have linked is for our Prezi Design product and not for Prezi Present.
You can add your images to Prezi Design following this article or you can add your images in Prezi Present. In Prezi Present PNG images with transparent background should be inserted with transparent background as well. If this does not work I would ask you to send me the image so I can test this further.
If you chose to send me the image I would ask you to send it via wetransfer.com, please make sure to create a transfer link instead of sending me an email.
If your images do not have a transparent background but you want to add them to Prezi Present with a transparent background, you can also edit them first in Prezi Design. Add the image to a blank project, resize the project canvas or the image so that they fit, and then remove the image background as described in the article you’ve linked. Next, you can download the project with this image as JPG with a transparent background: click the download button in the upper-right corner of the editor, choose JPG format and enable the Transparent background toggle on the right side of the download page.
Here’s also a tutorial on downloading in Prezi Design.
THank you so much for your reply. That was super helpful! I hadn’t realised they were two separate entities. I could have sworn the last time I was using prezi, I managed to do everything in one place.