Macos – Change background and font colour in mac terminal

In Tiger you could select background images in Preferences, but that went away in Leopard. The .terminal files can be exported and imported as a xml property list. The plist "key" node value for the background image is BackgroundImagePath followed by a "data" node that contains a base64 encoded binary property list that has a "string" node pointing to an image file.

<key>BackgroundImagePath</key>
<data>
...base64 encoded binary plist here....
</data>

You can use openssl to decode the data content.

openssl enc -d -base64 

Then convert the binary plist to xml using plutil.

plutil -convert xml1

You will see something like this...

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
 <key>$archiver</key>
 <string>NSKeyedArchiver</string>
 <key>$objects</key>
 <array>
  <string>$null</string>
  <string>/Users/user/Pictures/myimage.png</string>
 </array>
 <key>$top</key>
 <dict>
  <key>root</key>
  <dict>
   <key>CF$UID</key>
   <integer>1</integer>
  </dict>
 </dict>
 <key>$version</key>
 <integer>100000</integer>
</dict>
</plist>

Change the image path and convert the xml plist back to binary and base64 encode it.

plutil -convert binary1
openssl enc -base64

Then set the value of the "data" node to the base64 string.

It may be related to your $TERM env var.
See what $TERM is currently set to:
echo $TERM;

I tested this export TERM=xterm-256color on a newer version of macos with vim 8.0. and :terminal is correctly displaying a white background.