This has been driving me absolutely bonkers. Even though I’ve resized some of my problematic featured images to the 1920x550 number I keep seeing, and it doesn’t matter - it still looks like the photo is centered when it appears in the slider, instead of filling the entire slider box. The REALLY irritating part is that not every image does this.
You can check out the site at www.tworestlesshomebodies.com. I think one of the first images that slides through will demonstrate the issue pretty clearly. Any help you can provide would be much appreciated!!
I hope you are well today and thank you for your question.
It seems you are using Jetpack plugin on your site so could you please try temporary deactivating it or its Photon module on your site?
This jetpack photon module is not updating the images stored on wp.com so to resolve the issue either disable this module or update the images on wp.com by contacting jetpack support team.
The recommended image width for the slider is 1920px X 550px so please make sure your slider images are at least of size 1920px X 550px
Also use the following plugin to regenerate thumbnails on your site.