Instead of clicking on "insert image" do the following:
1. Use your photo editing software to change the image to a jpeg and make sure it is less than 100k, or it will not fit here.
2. Click on "manage attachments" at the bottom half of the posting page.
3. Follow the instructions there to find the picture file and upload it.
4. If you only upload one picture per post, it will show up automatically as a picture embedded in the post. If you upload 2 or more pictures per post, they will be shown as a link that must be clicked on to view the picture.