We've put together a script that we're hoping to get added to LEGO Answers that will allow users to easily insert images of Bricks, with or without links, and also links to sets on various listings sites via simple tags.
The supported tags are:
Draw a part (Technic Brick 1 x 2 with Hole) in a colour (red).
Draw a part (Technic Brick 1 x 2 with Hole) in a colour (red) and link to it on Peeron.com.
Link to set 5590 on Peeron.
Link to set 5590 on BrickLink.
Link to set 5590 on BrickSet.
The script makes use of the jQuery replaceText script and therefore must be used in a way consistent with that plugin's dual MIT/GPLv2 license.
install / update script | Source - Updated 06/07/18
The following question and answers has some codes in comments and my answer that will show this in action:
The script should work under all major userscript-supporting browsers, however it's currently only been tested in Chrome with Tampermonkey and Firefox with Greasemonkey. Please file a bug if you encounter any issues.
Zhaph - Ben Duguid actively maintains this script, with the bulk of the original code developed by Kevin Cathcart.