Search engines gives more priority to the sites that load faster and have less server response time. Whatever the quality and dedicated servers you choose for hosting, it is necessary to use compressed images on the site. Optimize images will be showing as the error message under "Should fix" category when you test the speed using Google PageSpeed tool.
High end content management systems like WordPress has many image compression plugins to optimize your images for search engines. But many other site builders like Weebly, Wix, etc. don't have the option to compress your images. You also need licensed software like Photoshop to create compressed images on your local computer before uploading to your site.