I am genuinely confused on why this app has such great reviews. The UI is nice, simple and clean, but iOS 8's stock Photos app does the exact same thing. From the Albums view, tap Select and you're able to select and delete multiple (or bulk) items at once. The only difference I see is the thumbnails are shown 3 wide, making them a tad bigger than the Photos app.
I'm not trying to bash this app or its developers, maybe I'm missing something (in which case I will gladly update my review), but this app seems redundant and unnecessary.