Answer 1

There are a lot kind of 'graphics'...

Html can handle ( at least most of ) them, but alone is limited to static graphics essentially.
Vector graphics ( since html5 ) can be handled as well as bitmap, through the open xml txt format svg ( while bitmaps formats web/html compliants are gif, jpg, png ).
3d graphics are more hard to handle, and it's usefull to look at frameworks dedicated, even if it's possible in absolute to use just Html to describe scenes.

Obviously, when using Html, you can't totally ignore Css.
And if you're interrested by handle graphics in html, you're probably didn't want to limit to static.
Since css3, you can animate pages/elements widely, only using css. That's means it's possible to "just" describe your page in text format, without real programmation. However, designing few complex graphics/animations by this way, "manually" becomes quickly hard-work and unproductive. So use of code becomes helpful for a minimum of automatization: in making scripts at least to generate static contents, animations data ( who could be called "static animations' ^^ ), with any languages ( the purpose is to generate static text files ), if it isn't in dynamicly handle generation and/or animation of graphics with JS ( wich is the only available on web brosers/html ).

About 3d graphics:
Whitout frameworks ( which means knowing a coding/scripting language ), you still need use/knowlendge of JS, and in addition you have to acquire skills in specific and quite complex specificities of html5 plus of libraries/descripting 3D languages as OpenGL...