Converting of MP4 to Gif

Hi Adobe Express, I've noticed a problem when using the tool convert mp4 to gif. When using it it seams to destroy the original file size. So if i make a size for example 2500x550px as a template in a project then when I use the convert tool my file afterwards will be converted into 1146 × 146px witch ruins my format. I don't know if anyone is seeing this problem as well but hope that you will be able to fix it.