Thank you for reaching out to us with your question for steps to compress the photographs as much as possible without losing quality.
Unfortunately, Photoshop Camera currently does not have this option. The team is working very hard to improve photograph quality, taking your feedback into heavy consideration. Stay tuned!
We would love to hear your thoughts on improvements and encourage you to submit them to the Adobe Photoshop Camera Forum here: https://photoshopcamera.uservoice.com/
Please feel free to also cast your vote on a similar request for the following feedback idea here: Can we have an option to save the photo in higher quality
Again, thank you for your valuable time and attention. Please don't hesitate to contact us should you have any further questions.
We would love to see you on social media platforms. Use #PhotoshopCamera when you post for a chance to be featured on our social sites. We look forward to seeing what you create!