A few newb questions about Troff typesetting

[katt16777216]

Hello, this isn't going to be about any bugs.  So far, I haven't seen any bugs. 
 However, I would like to start by asking a few n00bish questions I have 
regarding Troff typesetting in general.  So, here we go.  I also assume that 
some features I may be talking about are only available in GNU Troff, but since 
I am using GNU Troff anyway, it really doesn't matter if it's Groff-only.  I 
will be fine. :)

1) How do I use colours inside documents?  For example, I want to colour a word 
blue.  Also, are there ways to colour graphic primitives as well?  How about 
invert all colours?  Basically, how is colour-trickery done?

2) How do I include pictures in my documents?  Pictures in this sense mean 
real-life pictures, like the ones in JPG or PNG.

3) Is the `-dpaper` option the proper way to set the paper size?  Are there 
more proper ways?

4) Given a TTF file, what is the best way to add custom fonts?  I have actually 
added a few fonts with success.  I was able to successfully add and use 
EmojiOne SVGinOT (https://github.com/eosrei/emojione-color-font) on Troff using 
ttf2afm and afmtodit and the textmap table.  Some fonts don't work, though.  I 
have no idea why.

Thank you so much! :)