Pageflow can process almost all image, audio and video formats and automatically converts uploaded files into different target formats and output qualities. All media formats should be available in a high quality and should not have already been compressed into web formats. This is because if media that are already heavily compressed are compressed again, this can lead to poor results.
When a story is visited, Pageflow checks the respective network situation of a user and then delivers the best possible quality of a file. This enables a smooth performance, even in the somewhat slower mobile network.
In general, we recommend uploading images and videos with a 1080p resolution (1920x1080 pixels) or higher, up to 4K. Pay attention to high-quality photos, graphics, audios, and videos in HD quality in a 16:9 format. This aspect ratio roughly corresponds to the screens of most desktops and laptops.
Pageflow always zooms into background images and background videos to provide a full-screen display on all screen sizes and aspect ratios. Essential content, motifs, or graphics should therefore be positioned within a "Safe Area" so that they also work in portrait mode (9:16 within a 16:9 background). Use the motif area feature to mark the key part of an image or video and keep it visible on smartphones.
To further optimize the display on smartphones, you can also upload separate mobile versions of images and videos. You can find more background on vertical storytelling in this blog article.