Docker images and volues consume space on your computer. To get a birds eye of the usage do
$ docker system df
Which yields something like this:
$ docker system df
TYPE TOTAL ACTIVE SIZE RECLAIMABLE
Images 247 27 44.08GB 35.78GB (81%)
Containers 43 5 413.9MB 357.1MB (86%)
Local Volumes 383 44 83.1GB 72.25GB (86%)
Build Cache 0 0 0B 0B
To sort images by size:
$ docker images --format "{{.ID}}\t{{.Size}}\t{{.Repository}}" | sort -k 2 -h
2cb0d9787c4d 1.85kB hello-world
6d1ef012b567 4.21MB alpine
67f994af8639 4.81MB gliderlabs/alpine
b955fa398a69 4.82MB alpine
d88a70313556 5.27MB gliderlabs/alpine
f5df0abec1ac 6MB d4d/mu-memcached
a64ac7d97ed6 6.27MB d4d/mu-nginx
0eaa2395ed48 6.92MB memcached
...
e7671d9424c2 911MB node
c5f1efe092a0 912MB node
adc3ac86765f 918MB node
8118255d5cd9 978MB api-backend_api-backend
4125aa86ea9a 1.44GB devwithlando/pantheon-appserver