Gimmage is a small gtk image viewer, perfect for command line usage as it accepts directories and image filenames as arguments. It also has a filechooser integrated into the main UI, making accessing images and directories a snap.
FlowVision Alternatives
FlowVision is described as 'Waterfall-style image viewer for macOS, offering a smooth and immersive browsing experience' and is a Image Viewer in the photos & graphics category. There are more than 50 alternatives to FlowVision for a variety of platforms, including Windows, Linux, Mac, Flathub and Flatpak apps. The best FlowVision alternative is IrfanView. It's not free, so if you're looking for a free alternative, you could try IrfanView or XnView MP. Other great apps like FlowVision are ImageGlass, nomacs, FastStone Image Viewer and XnView Classic.