I would like to encourage everyone to come here and post their new planet textures. Either zip them or embed the PNG. Eventually we can build up a new collection. If you have an image of a planet you want me to convert for Distant Worlds, then just post it up or PM me.[:)]
A selection of these images were taken from The Celestia Motherlode addon repository site for the 3D space simulator Celestia.
Credits -
Creator - fungun
Creator - Zhar2
Creator - jestr
Additional Textures, models, addons - Cormoran, Don edwards, 3d duckboy productions, 3d.concept40.com, John M. ,Dollan , Andy Roberts, Steve Bowers, Ivo Beckers, http://galaxistar.googlepages.com, Matt Davis, Selden Ball, Runar Thorvaldsen, Rob Sanders, Cham (from Celestia forum), Pericapolis, Fridger Schrempp, pioneerxtower (J. P.), Bruckner, Shcuf, Jean-Marie le Cospérec
Thanks to Baleur for supplying the Eve planets.[;)]
Barren Planets by ConflictX.
Additional planets by Kalthaniell.
Installation -
1. Backup your \Distant Worlds\images\environment\planets folder by copying and pasting it somewhere safe.
2. Unzip to your planets folder and overwrite files when prompted.
Here are all the latest planet and cloud overlay retextures as of 26/07/2012:-
DOWNLOAD: http://www.gamefront.com/files/22038456/New+Planets+standard+res+-+260712.zip
For the high res pack, download here. However these do not include the volcanic overlays, so some volcanic worlds will appear very dark. Performance reduction is also not deemed worhwhile.
DOWNLOAD: http://www.filefront.com/17459676/New-Planets-311010.zip/
WARNING

Installation of individual planets -
Backup your \Distant Worlds\images\environment\planets folder
Copy the image to the appropriate planet type folder for example, save Continental-0014.png to the \planets\continental folder.
I've named these images so they will directly replace the stock images. Remember to back up your originals.