there are ways to do this, and different methods have different limitations / hurdles. maybe take a look at the threads below, and see if anything mentioned there might work for you:
- Downloading photo permissions - General - iNaturalist Community Forum
- Easy Way to Export Into A Field Guide - General - iNaturalist Community Forum
- Add option to download all my photos and data - Feature Requests - iNaturalist Community Forum
there are also tools like Microsoft BI that might help to do something similar to what’s described in the second item above (though i would guess most people will have a really hard time using something like that, or maybe that’s just me being too pessimistic).
that said, if looks like you have a ton of observations, and each “original” sized photo is ~2.5MB. so maybe consider downloading only the observations you really want to download, or at least breaking things up in batches.
also… if you’re going to download a bunch of media, it might be good karma to make a(n extra) gift to iNaturalist to cover the cost of all the extra traffic.