Please try and test this.
Post a test observation and get the picture addresses (copy the picture url). e.g.
the pics are:
(big pics) https://api.ispotnature.org/storage/app/sites/default/files/frontend/21890/201710/1454904_cuts/large_P9261151.JPG
& (Thumbs) https://api.ispotnature.org/storage/app/sites/default/files/frontend/21890/201710/1454919_cuts/small_P9301193.JPG
Then try editing it several times until the Edit Observation Wizard uploads without the pictures. edit and save.
I am willing to bet that afterwards the pictures will still be there, even though the observation shows no pictures.
Please test my hypothesis (logic: if the wizard loads without the pictures, it wont know which pictures to remove, so they will just stay there)
In which case the bug is simply: when and why does the Edit Observation Wizard load without the pictures? Is it during the GET, or during the page compilation? If it does not load the correct pictures, why is it not being detected and fixed without any need for the user to be aware of the issue?