Post Thumbnails multiple sizes

Simply naming the size in the functions file is not enough to get the sizes to work:
To call a custom size that you added do this:

<?php the_post_thumbnail('category'); ?>

I see you set_post_thumbnail_size(200, 200, true) which you don’t need to do if you’re also naming a post thumnail size the same sizes for homepage. Perhaps this line is messing up your other sizes.

Also, the_post_thumbnail doesn’t usually work on images already uploaded. To test if the sizes truly aren’t working upload a new file after adding the new thumbnail size/calling it in your theme file.