If you scroll by an image and tap on it, then I think the image should open up in full screen.
Right now tapping the image on the feed opens the post where I then have to tap it again. This isn’t the worst but doesn’t a feel smooth. Especially because a slight delay is required between the two taps. If you mess that up then you have to tap it three times.
I think Mlem is on track to be better than Apollo was at this rate. You gotta remember, Apollo had been released and in continued development for years. Mlem is around 2 months old