Stolen iPhone: Unbacked photos after iCloud storage upgrade?

You could try buying more iCloud storage, and waiting, then checking iCloud again, but success is by no means guaranteed.

For this to work,

• You would need to have had iCloud Photos turned on before the phone was stolen. Or, if you weren't using iCloud Photos, you would need to have the phone set to do automatic iCloud backups, and to include your photos in those backups. (In this second case, there would be no good way of seeing photos other than by restoring a backup to a second phone, wiping that phone in the process.)
• The phone needs to have remained unmolested
• The phone needs to be connected to Internet service … and chances are, if the thieves have it, it won't be near any Wi-Fi access point to which it will automatically connect. Even cellular Internet service might be lost if the thieves have taken it far enough (e.g., shipped it to China), turned it off, or placed it in a special kind of bag for the purpose of blocking all radio signals
• The phone needs to have power and be turned on
• The phone may want to be connected to power, so it thinks it is a good time to do synchronization or backup
• The thieves need to leave the phone turned on and unmolested long enough for it to finish a synchronization job
• The issue needs to be with iCloud storage being full, not with the phone's device storage being so full that there is no longer enough free space for it to function correctly
• The phone needs to have been programmed so that it will still try to do synchronization and make backups while in Lost Mode.

That seems like a lot of "if"s and it is quite possible that you could purchase the extra storage and not get anything extra in the way of photos back. So, the question might be, do you want to buy the extra storage and wait for a few days on the off-chance that you will "win the lottery" and that it will be "Christmas"?

If the storage on the iPhone was full, adding more iCloud storage won't solve the problem with the phones limited storage.

Some background operations remain active, but if it's not plugged in, the phone may not try to sync, and the battery will die.

michellle176 wrote:

Hopefully they will not be able to use the phone as Apple said they won’t be able to get into it

If your iPhone or iPad was stolen - Apple Support

"Apple will never contact you to say that your iPhone or iPad has been found. Never share your device passcode or other account information (such as passwords or verification codes) with anyone else.

Stay vigilant to avoid social engineering schemes, including phishing messages, phony support calls, and other scams."

Do's and Don'ts for lost iPhones - Switched Off - Offline - Beware of Phishing – Apple Community

"Don'ts

If the device is removed from an account after it is erased, Activation Lock will be turned off. This allows another person to turn on and use the device."

michellle176 wrote:…I’m not sure what to do

It sounds like you're OK. The only suggestion we had was the very one you started with--buy a month's worth of iCloud and see if it works. It only costs a couple of bucks. I'd guess you're going to get another phone, so you might find the extra iCloud storage useful, anyway.