Featured Image Not Resizing past 1200px

When I expand my browser (Chrome) past 1200px, which causes the sidebar to expand slightly, the featured images of my posts stop enlarging. The image I’ve tested is over 3000px wide. I’m using Sparkling 1.2.1. Any ideas?

Could you please post your website URL or screenshot so I can have a look?

Featured images (inside posts) are set to 750px x 410px and they won’t get bigger than that under any circumstances. Content area (both slider and content together) equals 1170px (1200 - 15px margin on both sides) and it won’t get bigger than that either. Like you said, above 1200px nothing happens and that’s how it should be.

For slider, however, images are not resized at all which means that it will display the same size as you uploaded. Even 3000px will work that way.

Ah I understand now. The featured image in a post has to retain the aspect ratio of 750x410 which is 1.83:1. My images were 3:2 and reaching the image height maximum first.

Is there a way to bypass this and just set it to 750px wide and no height value? This way the user could bypass cropping images to specifically meet the 1.83:1 ratio and use more common aspect ratios like 4:3, 3:2, 16:9.

Actually I don’t know why I didn’t make it to 750 x 420 px which would make it closer to 16:9.

You can change featured image size via functions.php. Current featured images are defined like this

add_image_size( 'sparkling-featured', 750, 410, true );

Making second number to something like 9999 would mean that featured images would always be resized only based on width instead of height.

Once values are changed in functions.php you will have to regenerate thumbnails because WordPress doesn’t do it automatically for posts that are already published. You can use plugins such as this to autoamte this process: http://wordpress.org/plugins/regenerate-thumbnails/

Thank you very much!