Perfect.
This is precisely in line with one of the expected outcomes I discussed in a reply to george_c:
From this, we know that your workflow can, and is being triggered by iPhone synced files perfectly fine, and even better, it is triggered by both the appearance of the placeholder file (the .icloud file) denoting the start of the syncing process, and its eventual renaming to become a .png image file denoting the completion of the sync. That’s basically the ideal outcome.
It means that, whatever is preventing your workflow from doing what it’s supposed to is happening inside the workflow itself, which will require further investigation (isn’t debugging fun ?)
What I would be inclined to do next is to take this diagnostic workflow, which contains that one shell script action, and reactivate the first action from your original set, namely Filter Finder Items. You would want to put your action first, and my action second.
Delete previous trigger files generated from your earlier tests. Then run the test again with those two actions. Basically, we’re going to isolate the point in your workflow where either there are no files generated, or there is one file generated but the file path inside it is not for the fully synced image file (e.g. /Users/bernardo/Library/Mobile Documents/com~apple~CloudDocs/PNG).