rkcel shows images on Terminals which support Sixel.
make
Usage: ./rkcel [OPTIONS] PATH
PATH: Filename of image file
(BMP, GIF, JPEG, PNG, TIFF, WebP)
OPTIONS:
-n N: Use N colors (N: max 255)
-d: Disable dithering
-m: Disable median cut
-c: Run calibration
-f: Disable fitting
-sb: Approximate bilinear scaling
-sn: Nearest neighbor scaling
-cover: Cover fitting
-wait: Wait enter key
-raw: Output raw Sixel