To get big pictures you have to insert the pictures url from imgur, not the picture itself. From the task bar in bladeforums app, choose the square icon with a sun behind a moutain. It is the one between the smiley face and film strip.
You will have 2 choices.
1 will be to link the picture, and
2 is to have the picture automatically show up in your add with no clicking. (Preferred).
GLWTS.