Output GIF size is much larger than the source file. Am I doing something wrong ?

[TejasShekar]

I have a 35MB 30fps screen recording. I wanted to share on GitHub as a gif to accommodate for the upload file size limit.

I imported the file to screentogif at 15fps. And in the "Save As" option, I didn't change anything. Left it default. Hit the save option. And the ouput file was over 100MB 😅.

How can a file that is playing at lower fps have a bigger file size ?

I also tried using the "Remove duplicates" as well as "Reduce FPS by factor of 1 per frame". The output of this was 70MB.

What am I doing wrong ? Why are my GIFs larger than the source file itself ?