Logo sliders quality

About Logo Sliders The image displayed on the logo slider automatically becomes low quality. This is the home screen of my website. Among the articles I posted, A is the one I posted last year, and B is the one I posted this year. I use exactly the same eye-catching image, but the image quality is different. I would like to post with A image quality. Please tell me the solution. Thank you. my website https://ruminakamura.com