Code inserted by you has the image path as you machine's local path that is incorrect.
Please make following corrections to your code.
1. Instead of using large file name please use small fine names such image1.gif etc (this is for the ease of coding and to avoid typo error)
2. Once you have the image renamed to a smaller name add those images to Assets folder in Muse by clicking on File > Add files for upload.
3. Now correct the SRC path of the images in the code and it will be "assets/image1.gif" (do the same with all the images you are adding in marquee and it should work now.
here is an example
<marquee behavior="scroll" direction="left"><img src="assets/image1.gif" width="120" height="80" alt="Natural"></marquee>
Regards
Vivek