Replays work but will give you very limited and sometimes wrong information. It may be fine to develop overlays on so you at least get some data, but it won't be a good experience to "broadcast" a replay.
For the widget image it sounds like you may have added it to the "Default image" property. Instead, you need the "Static background - Image" property. The default image is for dynamic images with data binding (the fallback in case there is no valid data binding).