Many thanks for that, which works fine.
But linked to it, is trying to keep the reduced image size of the main image, but it always changes the image size in the displayed grid.
article.blog-post .wp-picture img {
max-width: 50%;
width: 50%;
margin: 0 auto;
}
WAS
article.blog-post .wp-picture img, article.post-grid .wp-picture img {
max-width: 100%;
width: 100%;
margin: 0 auto;
}
Also if you check out a single post, the category text is half off the main image.