When importing your own content into Zinnia, technically there are no file size limits. Most of the time, you'll have no issues with your imports. However, for very large files, your app performance might be affected depending on your device's specifications. Larger files can make your device work harder to handle the data, which may result in your imports taking a little longer than usual.
If you notice any slowness when importing, it's likely due to the file size. A helpful tip would be to split the file into smaller sections and import them separately.
If file size doesn't seem to be the issue, it could have to do with the RAM on your device. We recommend at least 3GB for Zinnia to perform its best. If that's the issue, a reboot of your device will do the trick: power off, wait a few seconds, power back on!