Download video back into photos – iAlbum - Private Photo Album Review

Hi I can’t seem to download the video back to my original photos on iPhone. Other videos less than 10mins have no problems but a video of min that has 20 mins won’t download and can’t even send as a link to message. Please can you work on transferring a video to WhatsApp?? Directly from the app?
Review by Appealing to Apple on iAlbum - Private Photo Album.