Scale thumbnail image proportional with detection of longest side?

Hello,
I saw this thread and there is some pretty interesting advice here to look at "the module backend" for some more Resize Options. I cannot find the module backend! Where is it??? There are module options where it's only four options for thumbnails including "Thumbnail Image Width" Thumbnail Image Height" and "Preserve Aspect". Where is the backend with more options?

I am having a problem that the thumbnail image generated from the Article Intro Image is really blurry, i.e. I don't want the Intro image to be resized or changed in any way - is there a way to set it? Plus for some reason when the Latest News + picks up an Intro Image (i.e. my article image is loaded from Flickr, so Latest News+ doesn't create a thumbnail from the Flickr-based links) , it does not create a link to the article on that image like when it generates its own thumbnail from the article image - how can this be fixed?

Thank you very much for any help!