VFDecrypt Keys are not widely available for iOS 8. If the mounted iOS firmware version matches your simulator version, then you will discover much more artwork. Click it and you'll be directed to the file, which is in a Temp folder. You'll then see a blue link to the actual file at the bottom of the screen. decrypted.dmg in order to mount the disk image. In Disk Utility, select the decryptedfile.dmg. Go into the iPhone 4, 5.1 (9B176) folder or whatever folder was created depending on the firmware you chose.

Decrypting Image color format: grey size: 154x216 Decrypting Image color format: grey size: 86x102 Decrypting Image color format: grey size: 296x346 Decrypting Image color format: grey size: 132x164 Decrypting Image color format: argb size: 70x556 Decrypting Image color format: grey size: 238圆8 Decrypting Image color format: argb size: 504x556 Decrypting Image color format: argb size: 172x786 Skipping BasebandFirmware (ICE3_04.12.01_BOOT_02.13.Release.bbfw): No decryption key Downloading decryption keys from '(iPhone_4)'. You may use the '-o 'iPhone 4, 5.1 (9B176)'' switch in the future to skip this step. Extracted firmware to 'iPhone 4, 5.1 (9B176)'. The output should look like this: Extracting content from iPhone3,1_5.1_9B176_Restore.ipsw, it may take a minute. Run the ipsw_decrypt.py script on the firmware you downloaded or backed up.

Disconnect your iPhone from your computer.

Confirm that the backup was successful by selecting 'Preferences' from the main iTunes menu, clicking the 'Devices' tab, and then making sure that the time and date next to your iPhone's entry correspond to when you finished the backup.

Select 'This Computer' in the Backups section, and then click 'Back Up Now.' ITunes backs up your entire iPhone, including iOS, to the hard drive.

Click the button for your device near the upper-right corner of the iTunes screen, and then click the 'Summary' tab if it isn't already selected.

Start iTunes on your computer, and then connect your iPhone to your computer using its sync cable.

For beta versions, check the VFDecrypt Keys page instead.

Download an iPhone or iPad firmware that matches your simulator version and make sure that there is a VFDecrypt Key by checking the corresponding Build column.

Make sure to install the vfdecrypt binary somewhere in your PATH or use the -d option of the the ipsw_decrypt.py script.

VFDecrypt (required by ipsw_decrypt.py).

Python 3.2 (required by ipsw_decrypt.py).

You can extract even more artwork if you decrypt and mount an iOS firmware (.ipsw file).

Decryptedfile dmg