when ı upload a pic it goes to 404
and 1 more thing is ı cant upload more than 1 pic where ı need to upload 1 pic and then submıt it and then edit the topic and add the second picture its kinda complicated isn't t?
To be able to easily upload several images (or other files), you must buy the Adv Attachments addon from gvectors.
For your issue, the 404 is because the url is wrong, the "/yurtdisi-seyahat-rehberi/" is missing. You either have changed somehow the permalinks structure, or some plugin does that.