do you use Firefly on your Desktop Computer or Mobile? Right now the best way is to use a Desktop Computer. On Mobile it can be that there is not all functioning that well at this point, because of the Beta Phase. So, maybe try another Browser n your Desktop Computer and check if its also there. Hope that helps.
@Miraz30720860oz25 I was able to load an image into generative fill on an iOS device using Safari. What version of Android are you using? Also, this might sound weird, but does it make a difference if you tilt you phone to landscape mode?