Where to set the pictures ratio of the homepage article

Hello，thanks for your reply. I used 533px * 533px image as you suggested, but my homepage(http://suo.im/5VCC5I) display is still rectangular instead of like your(https://catchthemes.com/demo/fotografie-blog/) I want the proportion of the picture (like your demo) to be square instead of rectangular. Can you tell me how to set the ratio of pictures displayed on the homepage? Thanks! P.s I cannot continue to reply here(https://catchthemes.com/support-forum/topic/where-to-set-the-picture-ratio-of-the-homepage-article/)