Yes this has been disscussed before in other parts of this forum as BTD said, but as a quick help guide here's my version in a nutshell.
You will need a photo hosting sight like Photobucket, Fotki or similar, it won't work direct from your PC. They are free sites and are fairly easy to use, I use Photbucket.com. Open your account with whomever you choose, create an album, up-load your pics from your PC to there, resize the photos to suit the forum guidelines then using the 'Direct Link' copy the pic you want to post. Then back here at SA in the 'Post Body' Window you will see a Insert/Edit image icon 5th from the left, bottom row, looks like a pic of mountains and a moon/sun, paste the copied URL from Photbucket there and it should appear in your post.
That's just a quick and dirty version, so first thing is to go get that photo hosting site account set up, search this site for better answers than mine and then start playing around, there's a testing forum here right down the bottom of the forums page, do your test posts there and when you've nailed it get busy posting all your builds for all to see. It sounds like a lot of frigging around but once you work it out it's pretty easy, if I can do it you can too, I reckon from my camera to being pasted in a post, my pics take about 5 minutes to do, depending on your download/upload speeds.