It's not possible to deep link an images in Bannerflow, you can only add deep linking to texts (and buttons). So, in order to add links to an image you need to do a small workaround. The workaround is to add text fields that is covering the images you want to add deep linking to and then add deep linking to the text fileds.
Add the images
In my example I will add text fileds that covers the whole banner since I want to add the deep linking to the background images.
Start by adding the image/images to your banner.
Drag and drop one of the text assets to the banner.
Double click the text field and then delete its content.
To easily make the text field cover the entire banner canvas, right click the text field and click Fill to stage.
Make sure the text fields and the images are synchronized on the timeline.
Now, just do the same for all your images. And then 'Save and exit' the banner.
Add the Deep linking
When you have exited the banner and look to the right you will see the 'versions' section. Click the link icon as shown in the screenshot below.
Add the desired target URL and press 'Done'. You have now added deep linking to the first image. Just do the same for the other empty texts in your banner.
When you have added links to all empty texts in your banner you are done!