You may post in the gallery and garage areas of this forum( car photos only there,please). You may also sign up for a free account on a photo hosting site such as Photo Bucket. Once you upload your photos there you will see the tags have already been provided for you so all you would need to do is copy the link and paste it here.
Otherwise, you may upload a photo from you computer using the attachment controls or if the photo is located online use the [IMG] tags by placing [IMG] before the link and after it.
Hope this helps a little.