The photos in your profile or ad page are shown with a fixed width and height meaning if a photo is narrow, some of the top and bottom may be cut off. To get around this, on your ad/profile edit page, you need to zoom in then click on the photo and move it round until it looks good in the preview window. For full instructions click the question mark at the top of the photos column.

Once you are happy with the look of the photos on the edit page click the 'Submit changes' button on the bottom of the page and click 'Ok' in the pop up that appears. Then wait about 5 minutes for the software to redo your photos. You may need to refresh your browser window and even clear your browser cache before you see the changes on your public view of your ad or profile.