Welcome to the forum!
iNat does not provide a tool for downloading all of your observation photographs, though there is a feature request for that function: https://forum.inaturalist.org/t/add-option-to-download-all-my-photos-and-data/13722
It is still possible to download your photos, but it takes some effort. You can see some suggested workflows here: https://forum.inaturalist.org/t/preferred-ways-of-batch-downloading-a-subset-of-the-inaturalist-data/18342/7
Please keep in mind that iNat reduces images to 2048 by 2048, so if you uploaded images that were larger than that, you can’t get the full size image back from iNat.