add_image_size() and uploading the exact size leaves 1x1 image in uploads

Question

I've added an image size of 370x150 which works, but if I upload an image to those exact dimensions get_post_thumbnail() no longer works as expected. If I look into my uploads folder I'll have a thumbnail, medium, and full along with a 1x1. I add the image size like so:

add_image_size('homepage_featured', array(370, 150));

and call that image like so:

the_post_thumbnail('homepage_featured');

which then pulls up the 1x1 image size. I could probably circumvent this by adding a conditional before my thumbnail call which tests if that size exists:

$thumb = get_the_post_thumbnail($post->ID, 'homepage_featured');
$thumbArr = explode('width="', $thumb);
if(!empty($thumbArr) && is_numeric($thumbArr[1][0]) && $thumbArr[1][0] >= 370)
    the_post_thumbnail('homepage_featured');
else
    the_post_thumbnail('full');

but that seems silly. Is this a normal thing or is it a problem with my custom theme? Is there a better way to test if a certain thumbnail size exists than the above method?

Answer 1

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

Specifically note that the syntax is

add_image_size( $size, $width, $height );

What is likely happening is the array is resolved to false and defaulting to 0, as well as height.

As far as I know you can't have a 0x0 image, so it becomes 1x1 for that size.