You shouldn't clip the images (or at least not without some visual cue like fading), especially on a programming-related site where there's bond to be a lot of pictures of code and other text. This post: https://www.devrant.io/rants/59289 which is currently on the front page is a good example of why, it took me a while to figure out I was missing something.
There is also the problem when the image is squashed. It requires clicking on the image, which loads a new page with the image still squashed, and then clicking the image again to get it in a new tab.