A new BBcode has been implemented on the forum to allow for high resolution pictures without breaking the forum style. The only drawback is that the process is not automated so you have to link to two different pictures (the thumbnail that fits in the forum style and the original high resolution picture).
The code is the following; replace { with [:
{thumb1=http://www.mtm2.com/~mtmg/pics/FarmRoadView1.jpg]http://www.mtm2.com/~mtmg/pics/FarmRoadView1s.jpg[/thumb1}
which gives you
Alternatively you can use the "thumb1=" button right above the text box.