Thanks @Cesar_Pasache!!!
Got it to work, however. the .gif is always on and I would like it to be static until pressed.
Below is the script I am using. Let me know if you can recommend anything. Thanks!
tell application "BetterTouchTool"
set numFrames to 3
set startFrame to 0
set basePath to "/Users/mannyo/Documents/"
set baseName to "spaceinvader2-"
set extension to ".png"
uuid - https://docs.bettertouchtool.net/docs/apple_script.html
set widgetId to "4C36DFF3-850E-4DFF-9DC1-E4F433AFB1F4"
set varName to "anim-" & baseName & "frame"
try
set frame to (( get_number_variable varName) as integer )
on error
set frame to startFrame
end try
if frame > numFrames then
set frame to startFrame
end if
set_persistent_number_variable varName to frame + 1
set fileName to baseName & (frame as string ) & extension
set fullFilePath to basePath & fileName
update_touch_bar_widget widgetId text " " icon_path fullFilePath
end tell