With Firefox or Safari you save a web page—this one included—on a Mac using the same routine as saving any other file. Go to the File Menu in the menubar, or click on the page and open a contextual menu, then choose Save as…. That will open the same dialogue you've always seen, asking where you want the saved file to go but after that it gets a bit weird, because some of what you see are files, pictures and such held elsewhere and only briefly showing on your screen.
So the saved page has to suck all that crap off the web and onto your drive, in order that the saved page can be rebuilt without knowing today's addresses for the pic on Photobucket and eBay. Firefox will give you a file with an .html extension, and so will Safari but they re-write the HTML to connect with where the other bits get stored on your box and do it differently. I like FF's approach which is to put all the other bits in a folder with the same name as the file. DO NOT move or re-name either if re-opening the page matters. Safari hides all the bumf away for a cleaner look, but if all I wanted was to collect the pretty pix …
Both browsers offer other choices in their dialogues. Web page complete\Web Archive is the 'on yr machine' version of the page. But you can also select just the HTML code, just the Text and versions I've never cared about in the dropdown menu at the bottom of the dialogue. If you want to get back to the original page you will have to save a URL, a .webloc or a bookmark for it on your own.
Also very useful, though not quite what you asked is TextEdit, which can save any part of a page you highlight: pictures, formatted text, links by drag and drop, or by copying and pasting into an .rtf window. That can give you a document with active links out to the web. And as mentioned, any sort of 'photography' of the page\window or part of it is also available in the usual ways.