Greetings! This usually means it is an older asset with .texture files. There is a free utility by PEVSoft called Images2TGA. If you download that from PEVSoft and install it, then proceed as follows:
Right-click the asset in CM and select Open-Show In Explorer.
Then find the image asset from the error, which should be a somename.texture file.
If you double-click it, Images2TGA will open it.
Select "Save as", and Images2TGA will save it as a .tga image and a somename.texture.txt file.
Close out explorer and back in CM, submit the edits.
If it still says faulty, but there are no longer any other errors, double-click it in CM and the faulty will usually go away.