OK. To get the Google Earth image you want, have it on the screen in Google Earth, ctrl+alt+S should bring up a box asking you to say where you want the image saved as a jpg file. Then just load it to here as per normal.
What I do is make sure the image, photo or whatever you want to upload to the forum is small enough, then at the bottom of where you type your post, click on "Upload a File". The rest should be fairly self explanatory.
Pud