Gene Decoding of Surface Files/Parcellated maps

I find that the gene decoding function is greyed out for images I uploaded. Can someone advise on what format my maps have to be in in order to access the gene decoding?
I am working on parcellated images, and have tried uploading a nifti file and a surface file. Gene decoding doesn’t seem to be possible on either of those.
Thanks a lot,

Are the maps unthresholded and public? Could you share the link?

Hi Chris,
thanks, for getting back to me!
The image is:
Its a parcellated map, so by definition you will only find values in the cortex. No other thresholding has been applied.
I appreciate your support!

Unfortunately currently only maps covering the whole brain are supported.