Recovering deleted Telegram chats and photos on an iPhone can be tricky, as Telegram doesn't store messages on its servers once they are deleted. However, there are still a few methods you can try to retrieve deleted content, depending on your situation.

1. Check Telegram's Cloud Backup (if you have one)
Telegram stores all your messages (except those in Secret Chats) on its cloud servers, meaning you can access them on any device. However, once you delete a chat or photo, it is usually removed from Telegram's cloud. If you haven't manually deleted your chats or media, they may still be recoverable through Telegram's cloud.

Steps:
Reinstall Telegram: Uninstall and reinstall Telegram on your iPhone.

Login: Log back in using your phone number.

Check Your Chats: Your messages and media should be restored from Telegram's cloud, unless deleted permanently.

Important: Once deleted from Telegram's servers, there is no way to recover them.

2. Restore from an iCloud Backup
If you regularly back up your iPhone to iCloud, there's a chance that a deleted Telegram chat or photo may be included in an older backup.

Steps:
Check if you have a backup: Go to Settings > [Your Name] > iCloud > iCloud Backup.

Look for the date of the most recent backup.

Erase your iPhone: To restore from a backup, you'll need to erase your iPhone first. Go to Settings > General > Reset > Erase All Content and Settings.

Restore from iCloud Backup: After your phone restarts, choose Restore from iCloud Backup during the setup process.

Check Telegram: Once restored, check Telegram to see if the deleted chats and photos are available.

Note: You'll lose any new data created since the backup date, so make sure you back up everything else before proceeding.

3. Restore from an iTunes Backup (if applicable)
If you back up your iPhone to iTunes (or Finder on macOS Catalina and later), you can restore an older backup that may contain deleted Telegram chats or photos.

Steps:
Connect your iPhone to your computer: Use your USB cable and open iTunes (or Finder on macOS).

Select your device: Click on your device in iTunes or Finder.

Restore from Backup: Choose Restore Backup and select the relevant backup file.

Check Telegram: After restoring, check Telegram to see if your deleted data reappears.

Important: Similar to iCloud, restoring from an iTunes backup will overwrite your current data.

4. Check Telegram's "Saved Messages" or Chat History
If you've ever forwarded the deleted chat or media to your Saved Messages or another chat, you may still have access to that content.

Steps:
Search Saved Messages: Open Telegram, tap the search bar at the top, and type the content you're looking for (e.g., a keyword, photo, or chat).

Browse through Chats: If you forwarded the media to another chat or a contact, check those chats.

5. Use Third-Party Data Recovery Tools
There are third-party tools available that claim to recover deleted data, including Telegram messages and media, from your iPhone. These tools work by scanning your device's storage and attempting to recover files that have been deleted but not yet overwritten.

Popular Data Recovery Tools:
Dr. Fone (by Wondershare)

iMobie PhoneRescue

Tenorshare UltData

Steps:
Download and install one of these tools on your computer.

Connect your iPhone via USB.

Use the software to scan your device for deleted Telegram content.

Follow the on-screen instructions to recover your chats and photos.

Warning: These tools are not always 100% reliable, and some might require a purchase. Always read reviews and ensure you download from a trusted source.

6. Check Telegram's Secret Chats
If you used Secret Chats in Telegram, they are not stored in the cloud and cannot be recovered once deleted. These chats are designed to disappear after a set time and are not accessible from any other device.

Note: Secret Chats are device-specific, so once deleted, they are gone forever.

7. Prevention for the Future
To avoid losing important Telegram chats and media in the future, consider the following:

Use Telegram's cloud storage feature to ensure chats and media are synced across devices.

Export chats: You can export Telegram chats with media from the desktop app to back up important conversations.

Backup iPhone regularly: Enable iCloud backup or make regular iTunes backups to restore content when necessary.