Hi there!

Where do you put the image size, please?

However, you can use custom CSS either. Here is the sample code for you:

.article-list .article .article-feature-gallery img, .article-list .article .article-featured-audio img, .article-list .article .article-featured-video img, .article-list .article .article-intro-image img {
    width: 300px;
    height: 200px;
}

Hope this helps!

Best Regards