Q: How can I extend the amount of time that my client has to download their images (free or purchased)?
A: You can head to Selling > Selling Preferences, scroll down to the Digital Purchases section and set the Instant Image Download Timeframe option to as high as you need. The maximum is 180 days.
You can also adjust the Instant Image Download Limit while you are there as well. This controls how many times can your customers download their instant download digital purchases.