Easy to add pics.
Once you have the 'story' that you are editing open, click on the icon that has a pic of a mountain on it. The screen that opens up has 4 tabs at the top. Click on 'Image info' tab at the top of the page.
On the right hand side you will see a button called 'Browse Server', click that.
Now click on the folder called 'Stories'.

All the images that are in the various 'stories' in your site are here. To add a new pic from your computer, click the 'Browse' button (bottom of page) choose the image you want and then hit the 'Upload' button (bottom right of screen)
It is best if you re size the image to fit your story before you upload it.

You will now see that particular image in the list with all the other pics in the 'Stories' folder.

When you click on the image you want in your story (the one you have just 'uploaded') you will see it in a preview window.
Leave the 'Image size' / 'width - height' dimensions blank (as you have already sized the image before you uploaded) put in a 'border' of 1, add in an 'H Space' and V Space' (the distance of the text from the edge of the pic) of 5 or 10 ,align it to the left or right, and hit 'OK' button (bottom right)

Thats it!
(Don't forget to 'Save' your story before you exit!)