By default, the platform does not have this option. You can use the following CSS code.
Please follow the steps below:
1. Go to BuddyBoss > Theme Options
2. Under Custom Codes, enable CSS
3. Append the following:
.post-grid.bb-masonry .has-post-thumbnail.first .entry-img img{ min-height: auto !important; width: 100% !important; }
4. Save changes.