[Plugin: NextGEN Gallery] Non fixed thumbnail size intermediate size?

Hi,

I switched from Gallery2 to NextGen Gallery to have a better integration in my blog and after some testing, I’m very happy with it, but I have a problem. I perhaps miss something, but to make it simple, I’m looking for:

– Having 150×150 thumbnails in the album pages
– Displaying in the gallery page thumbnails (or intermediate) images of 500 px large but without vertical constraints for the size (500×250, 500×1754, 500×600, etc…)
– when clicking on this 500px large image, opening the full size image (through the mode define in the settings)

Right now, I was able to manage something similar with thumbnails of 500x500px, but it generate cropped thumbnails for the gallery pages and then, for the gallery album pages, I have 150×150 displayed through CSS, but it loads pretty big files just for the album lists.

What I want, is to have all the images displayed in the gallery fill the width of the content column of my blog, but uncropped, but still keep square small thumbnails for the album pages (and the widget), and if possible, without using CSS.

You can check my gallery here (Sexy girls, NSFW, but no porn):
The Album pages which list the galleries: https://www.meuuh.net/galerie
an example of gallery: https://www.meuuh.net/galerie/les-collections/cosplay

Thank you for your help (and for providing such nice gallery!