Pass $size and $attr to post_image_html filter

[waltervos]

It seems strange to me that get_the_post_image accepts $post_id, $size and $attr but when the filter post_image_html is applied, these parameters are not passed to it. This way, when $html is empty (when an image wasn't found) a plugin author only has $post_id to work with it. If you wanted to make a plugin that will use a default image where no post_image was found, you couldn't. A patch is attached to this ticket to illustrate what I mean.

[scribu]

diff format

[markjaquith]

(In [12211]) Pass some additional variables to post_image_html filter. props waltervos, scribu. fixes #11167