Hi,
Welcome to the forum!
If you want to get the image editor and the option to set for wallpaper, you can re-install the software using the Nokia Suite. Before updating, you need to back up your data to avoid deletion.
Use this link to download the Nokia Suite: www.nokia.com/nokiasuite
Follow the steps below to back up your files:
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Connect the phone you want to back up to your computer with a USB cable. On your phone, select Nokia Suite (or PC Suite) and then select OK.
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In Nokia Suite, click Tools then Backup. Nokia Suite shows you a list of the content types that you can back up and prepares a list of information that can be backed up.
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Select the information that you want to back up. If you want to change where the backup file is saved, click Browse and choose another location. If you have a lot of music, photos or videos on your phone, including them in the backup will cause the backup process to be slower.
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Click Start to begin backing up. Do not disconnect or switch off your phone during the backup. If you need to stop the backup, click Stop. Nokia Suite will reach a safe stop point and will then stop the backup.
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Click Finish to close the window after the backup is complete.
To re-install your phone software, select Tools then Software updates and select the word Re-install. If an update is available for your phone, you can see it here along with any other updates that are available.
If the above steps didn't work, can you tell us if you updated the software? There are some cases that, once you've updated the software, other features will be deleted on the next update but it'll be added a new feature and/or functionality.
Hope this helps. 
