Importing posts with images (Wp All Import)

Hello,

How can I do following? I’m importing articles from old system to new with WordPress. I’m using plugin Wp All Import. Now I got articles from old site where <img/> is determining place for image related to article. I’d like to know if I could do code to every <img/>-tag that could place image related to post in place. Like first <img/> shows the first image related to post and second <img/> show up second and so on. Can I do it with WordPress code or perhaps with All Import itself. First way could be better In my case so I don’t have to import those post again.

Thanks!