Podcasts Supported File Formats and Single File Size Limit

Here are the required/ standard file formats for image and audio files.

For Image
Podcast Cover -Between 1,400 and 3,000 pixels square (jpg or png)
Podcast Banner - Min size 1400px x 600px and 16:9 aspect ratio (jpg or png)
Episode Cover - Between 1,400 and 3,000 pixels square (jpg or png)

For Audio
MP3 Format 
M4A Format
Note: The audio file must be less than 250Mb