IOS device users may not be able to view/upload their receipt photos from Camera Roll within ExpenseWatch Mobile App. The reason is that ExpenseWatch Mobile App can only access the photos that are stored in the device's internal storage, not cloud.
You will need to disable iCloud Photo Sync from the Setting:
Step 1: Open Settings in your device.
Step 2: Navigate to Photos.
Step 3: Disable iCloud Photo Library.
You will need to retake the photo of the receipt. Or, move it to your internal storage.