Welcome to the forum kadars.
utnik's answer is correct for increasing the gap between the text in a frame and the frame it is in.
However, what you want to do is make the text flow around the image frame with a gap between the image frame and the text.
It's a subtle difference but an important one which wasn't evident in your original question.
Just a matter of knowing the right wording to use. It can be confusing at first.
This article might be useful:
http://write.flossmanuals.net/scribus/text-flow-and-typography/Otherwise you could do a web search for "scribus text flow around frame" (without the quotes) where you will probably see other articles and some videos.