You probably want to go into each of the numbered folders under [starmade]/data/textures/block/Default and remove the *.png and *.tga files. I believe they should then re-extract automatically when restarting the game, but if not you can either extract each of the *.zip files manually, or delete the *.zip files and use the launcher "repair" option to re-download the texture files.
This is based on a similar occurrence that I helped someone else with a few days ago; something related to the Steam download/update apparently? If you're uneasy about doing this, open t000.png and the version in t000.png.zip and compare them, and maybe post them for further advice/analysis. (If you see a cannon computer in that file, it's a very outdated version of the file.)