wkhtmltoimage binary is not included in this buildpack.
This buildpack only installs wkhtmltopdf, it isn't very useful by itself. You'll probably want to use add it to you current buildpacks config.
$ heroku buildpacks:add https://github.com/notvad/wkhtmltopdf-buildpack
Remember to clean your repository cache if you are updating the version of buildpack. To do that, run:
$ heroku plugins:install https://github.com/heroku/heroku-repo.git $ heroku repo:purge_cache -a appname
If you run into issues when trying to deploy with this buildpack, make sure your app is running on Cedar with Ubuntu 14.04 (
cedar-14). You can check this with:
$ heroku stack
If you are on an older stack, you can upgrade to
$ heroku stack:set cedar-14
Copy the snippet above into CLI.