Down swipe to close an image

I’m playing with few different iPhone apps. So far thunder is the one I like the best. But I have one big annoyance: when I open an image, and I want to go back I swipe down to close the image. Unless I swipe from dead center in the image and if I don’t swipe all the way down the screen the image won’t close. So every time I want to close the image I have to swipe 3 or 4 different times before I do it just right.