Regarding the clipping of the image, assuming you can be bothered, you could try this:
1. Upload two versions of your image to wherever you host them: one about 640 pixels wide for display on the forum, and a larger one for standalone display.
2. Use the following code to add your images to the forum posting:
That'll give you a smaller, unclipped image in the forum posting, which is a link to the larger image.
Try any of the postcards I've posted to see it in action.
Alan