I just found a working extension and installed on chromium! "Block Image"
https://chrome.google.com/webstore/detail/block-image/pehaalcefcjfccdpbckoablngfkfgfgj
It only has On/Off, but is saving my 100MB quota!
udpate: now using "HTML content blocker" from this tip https://superuser.com/a/1122390/157532
also,
as the accepted answer was about FireFox and not Chrome (therefore I think the OP subject could be changed)
I would like to add this alternative to Linux:
I've been using konqueror most of the time, I just open chromium if I need something specific that works better there.
here the adblock cfg I use that you can import on konqueror:
[AdBlock]
http://*.bmp
http://*.flash
http://*.gif
http://*.jpg
http://*.png
https://*.bmp
https://*.flash
https://*.gif
https://*.jpg
https://*.png
https://*.googleusercontent.com/*
https://encrypted-tbn*.gstatic.com/*
https://graph.facebook.com/*
the last 3 are meant to block images that come w/o explicit extension, have fun adding others :)
if you need to see images once, just keep the settings popup opened and enable/disable the adblock checkbox, quite practical.