imgcat

imgcat is a command-line tool that pipes local or remote images into the terminal, rendering PNG, JPEG and animated GIFs using the iTerm2 inline graphics protocol rather than ASCII art.

This tool has stdin support, automatic detection of terminal columns, fit or explicit resize via --width and --height flags, lanczos or nearest resampling for quality control, transparency preservation, animated playback, interpolation switch, top offset positioning, plus a silent flag to omit status messages and true-color override for misconfigured emulators.

You can use imgcat to test out displaying images in the terminal to see what they would look like.