[FIX] Fixing image missing when using description

when inserting images with the attribute type="attId" and desc="Image below" in the example of {img type="attId" attId="2" desc="Image below"} the image was invisible. while fixing on the idea that the image is supposed to appear I proceeded by checking the different pieces of code linking to the img plugin the one that allows to call an image inserted in the database. The solution found after the multiple tests was to give by default to the call of the image a predefined size at 100% heigh and 100% width, of course if the user does not set any value and in the contrary case the inserted image will take the size predefined by the user.