Thumb URL perview as Video URL not image, File Extension not updated

[ghost]

gem 'carrierwave'
gem 'streamio-ffmpeg'
Rails 7 Ruby 3
Failed to update the extensions

, [2023-07-19] INFO -- : Running transcoding...
["/usr/bin/ffmpeg", "-y", "-i", "1689766990-977250766eeee392977-0025-7931/thumb/SampleVideo_1280x720_1mb.mp4", "-ss", "2", "-s", "640x360", "-q:v", "2", "-vframes", "1", "-f", "image2", "-aspect", "1.7777777777777777", tmp/1689766990-977250766392977-0025-7931/thumb/thumb.jpg"]

I, [2023-07-19] INFO -- : Transcoding of tmp/1689766990-977250766392977-0025-7931/thumb/SampleVideo_1280x720_1mb.mp4 to tmp/1689766990-977250766392ss4444444977-0025-7931/thumb/thumb.jpg succeeded

In preview the URL work as VideoURL not as Image_URL.
File Extension: is not updated

version :thumb do
process generate_thumb: [:thumb, format: 'jpg']
end

def generate_thumb(*args)
FFMPEG::Movie.new(file.path)
reset of code
end