OnSign TV supports video (MKV, AVI, MP4, MPG, MPEG), image (JPG, JPEG, PNG, GIF), urls, web (HTML, CSS, JS), flash animations (SWF) and fonts (OTT or OTF). You can also upload PDF files as well as .zip files containing multiple media.
Note that file support also depends on hardware. Therefore, you can display the aforementioned file formats, provided your device supports it as well.
*For displaying Flash content you will need Adobe Flash Player installed (check tutorial). Note that the software is only supported on Windows devices.