All the images that I've tried have been the jpeg format. I tried the same sort of application, (create from image), with another programme, (Coolors.co. I don't know if you've heard of it?), and I got the same "The selected file type is not supported". The fault is obviously mine, but I don't know where I'm going wrong.
Could be that there is something wrong with the file. If the content of the file is not too sensitive you might want to share it with the color team at firstname.lastname@example.org. The color team may be able to tell what's wrong.