Hello,
Today I just found a new texture library:
texturelib.com (http://texturelib.com/), with a very good license for our purposes:
QuoteTerms of Use
All images are taken by my own cameras and edited by me.
They are free for commercial and non-commercial use with the only limitation: you are not allowed to sell or distribute original or slightly modified images alone or in packs. You can only distribute them as an integral part of your product.
Credit texturelib.com if it is possible.
Texture library © 2011 Dmitriy Chugai
Given the amount of viral GPL and CC-BY-SA licenses around, this one was worth sharing! ;)
EDIT: The site allows to 1 (one) free download per day, additional would be restricted to payment access.
However, due to my need to rescaling anyway to fit Pak128, I find that even the thumbnails & previews are more than large enough for my purpose... I hope the license holds also this way: I could easily have downloaded what I need day-by-day over 1-2 weeks.
You might run into problems if you want to distribute the source files to graphics you have created though.
Well, today I used one of those textures: I scaled down a 300*225 thumbnail to 64*64 and edited it heavily to be used in isometry.
Definitely the result is not an "original or slightly modified image", considering they distrubute it at 2000+ px.
If I distribute my PNG (crediting the site), I believe I fall under license terms, and Pak128 license doesn't force me to distribute sources of sources.
Another good one I found:
www.public-domain-image.com (http://www.public-domain-image.com/)
This one releases into Public Domain, so no license issues here! 8)
Did you check Burningwell? http://www.burningwell.org/
You can look at cc0-only textures at OpenGameArt as well... http://opengameart.org/textures/all?field_art_licenses_tid[]=4
Another ressources used by me sometimes :
http://www.freemages.co.uk/
(creative commons and free art license)