You can designate what type of media can be submitted for gallery entries in the Gallery Submission field. Accepted file sizes and formats are as follows:
Image Files:
Accepted Formats: .jpg / .png / .gif
Max file size = 15 MB
Video Files:
Accepted Formats: .mp4 / .mov / .avi
Max file size = 200 MB
Audio Files:
Accepted Formats: .mp3 / .wav
Max file size = 30 MB