YES! Even though we have a non-free option to remove watermark from downloaded video. You don't have to use it because you can achieve the same purpose by collecting shares from Facebook.
By default, slideshows are stored as html elements, which require relatively higher hardware spec, thus the replay may be slow on some mobile devices. By downloading it as a video file, you can get consistent replay experience on all devices. Meanwhile, you can post it to more popular sites such as Youtube.
Only slideshow owner could request for a download. To request for download, go to Account Manage page, find the work that you want to download, click request button near HD video or SD video field.
This site uses Google's account system. Create a Google account if you don't have one. When login required, you will be redirected to Google's login page and return when succeeded. We have no touch on your password, so you don't need to worry about your account's security.
Currently the application does not support caption editing. However there are many handy photo editing softwares that support caption. You can use them to implant captions in photos. By adding captions word by word and saving a copy at each step, you can even enable caption animation in slideshow.
Currently Android does not support such operation. You need load pictures one by one, or upload them to cloud with Google Photos, then load them from Google Photos option.
iOS does not allow user to load audio from browser. In such case, you have to load online audio from web.
No. The editor resizes images automatically at uploading, and its output resolution is always no larger than 1440 x 1080. Therefore higher resolution does not help if its active portion (the portion that is shown in slideshow) has more than 1440 pixels in width or 1080 pixels in height.
On the other hand, large files dramatically slow down image load speed. We suggest to resize images to proper size before loading it.
Canvas is a new feature of HTML5. It acts as backstage for slideshows. Although all modern browsers support this feature, you will get above message if using IE8 or older version. We suggest to update browser to IE10 or higher, or use Chrome instead.

For more information, see Pholody blogs with User help tag.