I'm setting setting the featured image as an image that is 700 x 320 so it works in the lightbox correctly. However when it using the same image as the thumbnail its squashes it. The thumbnail needs to be a perfect square. How can I set a separate image for the thumbnail?
How to use a separate image for the thumbnail2 posts from 2 voices
all widget thumbnails, etc. are auto-generated based on the first image you set for this post/page. It's not possible to set different thumbnail images for different dimensions without manual work/coding. I can give you some hints only because this mod is beond the scope of this support forum - you can use the post meta function: http://codex.wordpress.org/Function_Reference/get_post_meta and custom fields to set different thumbnails. Depending on the theme you're using you need to replace the thumbnail code with the get_post_meta function.
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