in my opinion if you would add a portrait orientaion, it would also be helpful since there are very few websites that are compatible with that. either ways i liked your overall website and is very helpful to use. you could also add more fonts and colors

Only widescreen (16:9) available here. It would be nice to also have the Standard (4:3) slide size option to cater for improved integration time to already existing presentations. Plus, that is a selling point for me since it would make make Wonderslide one of the few if not the only one with this functionality.