Learn about how to choose the right size when uploading files
There are no limits on file size, but please note that the upload speed is affected by how large the file is, so for large batches of files, it might be helpful to consider what size files you need. Also, note that no thumbnails will be automatically generated for larger files, so you must create your own thumbnails for any files exceeding a certain size.
Read more here: Why aren’t my uploaded files getting any thumbnails?