If you want to post a pic in a table for a Character, Location, Quest you have to upload the picture first. Then click the Add Photo button after the " = " at the " |image = " section. Your file will probably look like this |image = [File:Example.jpg|thumb]. With double [ and ].
IF you leave it like this the picture will not look great and will not be at the right proportions. For it to look good you must delete some things and it should look like this in the end
Next you must set the size of the image in pixels(px). Press enter then add a new line " |px = xxxpx "( I usually set the pictures for 250px so mine looks like this |px =250px ) . In the end the whole thing should look like this.
Now you have a right image even in a table.
I'm currently taking screenshots for some of the side quests and some items and i like to do it :D .