Hi Victoria, all of our photos are uploaded by our users! If you want to add to our photo collection, just click the Upload button at the top of the screen and upload them to your Projects!

The question was 'how' .
'Just push the upload button' does not answer the question.
I'm using an iPad and don't see an upload button.

@jmlemay: Log into your Houzz account via the web. You can do so by logging in through Safari or Google Chrome. Once you're on the website version, you will see the Upload button in the top right corner. Once you click on that, you will see where you can upload photos.

Found it

On the iPad it's in a different place. It's in the left column at the bottom

Of the Your Houzz tab.
But thanx for taking your time to try to help :)