featured image resize

HELP!! Sakin, Is there a way to bypass the resizing of featured images? Or - is there a way to get images from inside the post to show up in the excerpts? Compare the first image here: https://hidemyage.com/ To the way the image is here: https://hidemyage.com/dermal-fillers-to-wake-up-your-face/ I tried taking the featured image out of the post but then no image shows up at all. It's important in my industry that large vibrant pics show up on the main page. It's also important to use excerpts so they can see different subject matter instead of scrolling through the posts. Thanks! hidemyage.com