Sorry, how can I forget bout that. Anyway the
iframe are still served by Tumblr’s domain, so fortunately we could alter it with JS.
But unfortunately, it is not without problem, as we didn’t have a clue when are the photoset JS will do its calculation and execute it. So if we apply a JS css alteration to it, it will be overwritten as our JS will execute before Tumblr’s. A way I found that work is by using imagesloaded plugin by Desandro, and using the setTimeout function.
We wait until all the images load, and give it a 1 second timeout and apply an auto height to the
'height' : 'auto'});
What it do is, that once all the images is loaded, we wait for a second, “hoping” that the photoset script finished executing. Well it does work for me and you can check the first post at this thrash page.
Of course, this is not safe from any caveat. The timeout of 1s will mean that your photo height transformation will be pretty obvious, but that’s the only way I could get about it. There’s perhaps a better solution in the wild. I hope there is.