How do I put text/image on my webinar playback page?

Images (or text) can be added to watchpage at webinar, shown how to below from placing at field when configuring. Depending on the watchpage template you've chosen it will display in different areas.

Find Customize section when editing any individual webinar event as shown below,

Scroll down page to Configure Watchpage, notice (Preview link) there for when editing is complete!

You can add text, images, buttons, or template tags in the editor that you see there and then hit "Save" once you are done.

Let us know at the chatbox if anything is not setup exactly as you like, we're happy to assist!