WordPress change featured image default size

Question

I have a WordPress site and I want to increase the default size of the "featured image" for each of my posts to 500px by 500px. I tried simply resizing the image with CSS but they pixelate.

Any ideas? Sorry if this is basic - I'm a bit of a WordPress novice.

Answer 1

You need to create a functions.php file. And place this on your code:

if ( function_exists( 'add_theme_support' ) ) {
add_theme_support( 'post-thumbnails' );
    set_post_thumbnail_size( 500, 500 );
}

Answer 2

Try this in your function.php do

if ( function_exists( 'add_theme_support' ) ) {
add_theme_support( 'post-thumbnails' );
    set_post_thumbnail_size( 150, 150 );

}

http://codex.wordpress.org/Function_Reference/set_post_thumbnail_size

Answer 3

Your images are blurry because they they are set at a lower resolution than 500px x 500px. You can't scale an image up without loosing quality.

To fix this, create your images to the desired size in a graphics editing program like Photoshop