You can save rendered files in many formats including JPG if you want although I would recommend a lossless format instead like uncompressed .tiff or targa.
To save to a different format click on save as under the file menu of the render window.
As for a movie i would not recomend saving a file to a movie format straight out of Maya but insted save an image sequence and encode the movie using the sequence as you will get much better results.
Take a look at this free SM tutorial kindly made by Mike to help you with this exact process.
https://www.simplymaya.com/movie_page...html?tut_id=49
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