Yes.

When editing the data you're interested on the web there are options at the bottom for you to be able to upload your own photos if you don't want to use the ones captured by the app.

Also for data that uses sketches and diagrams, these can be replaced with your own too, if you'd prefer to enter a CAD drawing for example.

Whatever custom content you add will automatically flow through to the PDF deliverable.

See the article on editing data for more details.