Fitting images in preview windows on Post intro page

Hi there,

I have a introduction to posts page (selected as having 6 at a time) and it automatically adds an image I've inserted into the post page. This is fine, but I find that when they automatically come up in these preview windows, some of the sizes of the images are too big that they are cut off. I've tried re-sizing them in the post pages themselves but I'd rather have them the size I'd like on that particular page. I've attached a screengrab to show you what I mean. I'm hoping you can let me know how to fit the images into the preview window so you can see all of them.



[image pos="0"]

hope the attachment worked?