Based on the space exploration license, https://docs.google.com/document/d/1z-6hZQekEHOu1Pk4z-V5LuwlHnveFLJGTjVAtjYHwMU, you can't take the iridium sprites from the graphics mods and put them in your own mod. (note the part that says "You cannot distribute any content of the mod separate from the complete mod package.")
If you're unaware, you can use another mod's graphics without needing to copy them into your own mod folder, by using other-mod-name/images/whatever.png in the sprite definition, and can use sprite layers to create a composite sprite like you're using for the technology, without being in violation of the license. You can't do something like that for the mod thumbnail, though.
