Textra - Where are the photos hidden in this app?

[Android Central Question]

Trying to download to my pc ALL the photos from Textra. How do I do this? I have found that I could save a photo to the gallery but only one at a time. I want them all. Don't tell me about the setting to save all photos to gallery option - as this is ok going forward but what about the several thousand already on the app?
Sure wish Textra had support/manual.