You have 2 choices for inserting an image into PR body:
1. Put image url at right position in article(also work for youtube url in this way).
2. Put image according to below way.
Go to www.imgur.com, a third party free image hosting site, and upload your image.(If use image in your site, then ignore this step, and to Step 3 directly).
After the upload is completed, right click image, and copy image url.
Go to the Press Release Body section and click the image icon in the text editor.
Select “Image Info”.
Paste the link you copied from www.imgur.com (If use image in your site, then paste your image url)in the URL section and click “OK”.
Your image has been inserted in the press release body, and you can continue to edit the content.
You can click the preview icon to preview your draft.