Brummiebell - are you saying that you are seeing the thumbnail of the picture in the post, but can't get it to be larger?
Normally, clicking on the thumbnail will enlarge the picture - it is normally opened in a separate window to the post.
If you can give me an example of a picture that you can't enlarge, I will try to investigate. [To do this, right click the post in question (not the graphic), select Properties and highlight and copy the URL that is displayed in the properties box. Then, paste the link into this thread]