Someone over at XDA forums has managed to post all 9 new high-resolution wallpapers of the G3.
Phonearena also shared the LG G3 wallpapers package on Dropbox.com, But it seems that some one is getting the Error (509) with the download.
For those who want to download LG G3 wallpapers, Here you are the alternative download links:
Download: G3.zip https://mega.co.nz/#!RswAXJKR[15.81M]
Please let us know if you experience any issues with the download!