There are two ways to post an image to these forums.
1) You can upload an image to photo bucket (or some photo hosting service) then link the URL here.
2) (preferred method) By opening your image up as an image file you can/should be able to copy paste it here. This way you can put the image inside the actual post rather than making people follow a link that their work/school computer may not allow them to follow. Some have had issues with this in the past though so method 1) is a good backup.