These 2 variations worked for me:
Import Library ImageHorizonLibrary reference_folder=images
Library ImageHorizonLibrary reference_folder=${CURDIR}/Images confidence=0.9
I don’t recognise the editor your using, it could be a problem with your editor not recognising ImageHorizonLibrary being installed or it’s using a different python environment from the one where you installed ImageHorizonLibrary?
I’m a bit old school and don’t use code completion or fancy editors, I just use a basic text editor so I’m not sure I can help with this.
Maybe change the topic title to “xyz editor not recognising robot framework libraries” and then you might get the answer you need.
Dave.