Why some Imgur images doesn't appear in Google Instant Preview

DanielSemper 13 years ago updated by Alan Schaaf (Founder) 13 years ago 2
You upload an image to your account, you publish it in your blog, after some minutes, search it in Google, try the Instant Preview and you will only see the Alt text displayed (in the small preview)
here is what i think... google would give preference to images that are stored on the domain itself.

any outsourced image is treated as a possible ad block or an irrelevant material so is hidden from the instant preview.
Strangely this doesn't happen when you post images from flickr. (But I prefer Imgur service)