You can add as many images as you want to your already created slideshow. Follow these steps to do so:
1. Select the slideshow which you want to modify, and then click ⚙ to open slideshow properties.
Tip: You also can add images by clicking Element settings on the properties toolbar.
2. In the opened pop-up window, click any of the following buttons:
Upload: Upload images from your device.
Select from library: Select from previously uploaded images.
3. Select the images you want to add and, if needed, modify their order by dragging the image to the place you wish.
4. When you are done, click the Update button.