Well Doc, you can either upload them as an attachment (which drives me nuts but is usually the best way to do it from a phone in the field) or upload it to a third party image hosting service like Flicker and link to it from there.
For the attachment route, you need to "Go Advanced" when you're replying to a post and, below the area you type your response, you'll see an Attachments section. It should be self explanatory from there.
For the linking to the image from another source, copy the image URL and then click on the little picture icon at the top of the Quick Reply box (it's the one that is square with what looks like brown mountains rising up into a yellow sky with the sun/moon in the upper right corner). Just paste the URL in the box that pops up and again, from there it should be self explanatory.
2007 2.4 Base
MagnaFlow dual outlet, quad tip exhaust test car
60# injectors, Custom Tune, Custom Cold Pipe, DDM Probeam and Backbone, Venom Brace, BC Coilovers, Z0K anti-sway bars...