Photo cropped automatically in category

Hi there, I have a post on the home page with a photo crop that’s fine, and when you click on the title to go to the post page the photo is fine,
http://www.lotusfilms.co.uk/?p=560
however in the category list (film) the photo is automatically cropped. Help!! Any suggestions? I’m not a developer…
Here’s a link to how the image appears.
https://www.dropbox.com/s/sw551eyp519q9dw/photo%20crop.png?dl=0

Thank you for any help.