Images

Photographs may look good in a Prezi but "highly regular" images such as mathematical graphs will not look good, even if you make the image large. The best format for images in a Prezi is pdf. If making the image in GeoGebra, you can export it as pdf. For other images, you can convert jpg-images to pdf online at: http://www.freejpgtopdf.com/ (it doesn't work for all images)

Video

You can upload a video to Prezi but large-sized videos can make the presentation lag. In order to avoid lag, upload the video to your YouTube account and paste a link to the YouTube-video from within Prezi, the video will then be embedded in the presentation.

The embedded video will be shown in aspect ratio 4:3; if the video itself has aspect ratio 16:9, there will be a black region above and below the video. Since you need aspect ratio 16:9 in order for the video to be HD, you must chose between black regions and poor quality. For more information about HD and aspect ratios see: http://en.wikipedia.org/wiki/High-definition_video.

Web pages

You can input a link to any web page in Prezi (just paste it); when clicking on the link, you must leave Prezi and watch the linked web page from the web browser. If the web page you want to show isn't interactive (with clickable and draggable stuff), it might be a good idea to include a picture of the linked web page inside the presentation, thus avoiding having to leave Prezi. You can convert any web page to pdf online at: http://html-pdf-converter.com/, then upload the pdf-file to Prezi.

Mathematical Formulas

In order to get a zoomable mathematical formula you should save it in pdf-format.

If using Mac, use LaTeXiT to write formulas and save them as pdf.

If not using Mac, you can write each formula as a LaTeX-document and then save it as pdf; follow the instructions at this forum thread.