Same problem here. When using the image post format, clicking on the image (when viewing an excerpt on a pinboard style page) will cause the image to open up in a lightbox rather than going to the post itself. To make matters worse, if you have several image posts on a page, all of those images will open in that lightbox.
Needless to say, I do not want this. How can I disable this function?
The only reason I am using an image post format instead of standard is because the image I am using isn’t hosted on my site. It’s hosted elsewhere and therefore can’t be used as a featured image. Without a featured image, there is no image showing on the except on a pinboard style page.
This is also a problem for the gallery style post. The thumbnail for the gallery posts only uses three images. Clicking on it gives a lightbox of those three images only, rather than going to the gallery post itself.