I don’t know if this is truly a bug or if it is working as intended. But, I have some minor problems with “Featured Images” in the Archives pages. When you create a new post, the featured image for the archive pages is not generated yet, so it will show the wrong dimension until you hit F5. If you are using caching like me, you will need to flush the cache as well to make it generate the right dimension.
Also, I did a clean up and used a plugin to delete all unused image sizes and regenerate thumbnails. This resulted in the images used for the features image on the archive page to be deleted as well, because it is need specified via “add_image_size” function.
The custom image sizes are generated in the background, so it can take a minute to generate them depending on server setups. It’s definitely possible that you need to clear your cache for them to generate, depending on your caching.
The image sizes aren’t generated on the fly to prevent any server timeouts or issues.
We’re going to be moving to a new image resizer, which will utilize add_image_size().