How do I view inline images in w3m?
Things you need to make this happen on macos:

1. Terminal emulator that supports sixel

iTerm2 recently added sixel support for viewing inline images. You'l need iterm 3.3 or later, which at time of writing is in beta, available in the test releases section of the downloads page.

2. Utility for converting images to sixel format

I used img2sixel.

  git clone https://github.com/saitoha/libsixel # Download the source code
  pushd libsixel # switch to the directory containing the source
  ./configure # This generates compilation settings for your OS
  make # Compile the program
  export SIXEL_DIR=${PWD} # Store current directory for reference later

  # Test it
  ./converters/img2sixel images/snake.png #should display in your terminal :)


3. w3m build with sixel support

Follow the sixel readme in tats/w3m

  popd # Don't clone w3m within the img2sixel dir
  git clone https://github.com/tats/w3m
  pushd w3m
  ./configure --enable-image
  make

  # Test it 
  W3M_IMG2SIXEL="${SIXEL_DIR}/converters/img2sixel" ./w3m -sixel -o display_image=1 google.com


4. Install

If the above test worked, then the compiled img2sixel and w3m binaries can be copied into a dir referenced by $PATH, eg /usr/local/bin so you don't have to reference them explicitly each time you start w3m.