The templates Excerpt Plus, Excerpt, Slim Plus and Slim require a specific image size and can not be changed (changing the images settings in the admin will not have an affect). These templates will automatically create images from the original source image that are 120px × 100px with a center crop. If you require a specific crop for these images you will have to pre-process the image for the correct crop before uploading them to the entry. If you upload a pre-cropped image using the image ratio of 6:5 the resized image the template creates will maintain its crop.
For example if you have images that you have cropped the way you want the to appear in these templates with the dimensions of 200px × 167px and 110px × 92px you will have to adjust the image sizes to be the correct ratio first. Here’s the math equations that can be used to figure out the correct image sizes:
( width / height ) * new-height = new-width
OR
( height / width ) * new-width = new-height
We’ll use the first equation for the two example images sizes.
Here’s the math for the 200px × 167px image: ( 100px / 120px ) * 167px = 139px
What this shows is the first image width of your pre-cropped image will need to be reduced to be 139px so when it is displayed in the template it will be displayed with the same crop.
One more times with the second image 110px × 92px…
( 100px / 120 px ) * 92px = 76px
The width on this second image which have to be changed to 76px before being uploaded to the entry.