Yes. Let me elaborate. The -kb option tells CVS that the file being managed is "binary" and should not be "adjusted" for different platforms. If this flag is not checked. then files will have line termination translation performed, which will definitely mess up PNG and other image files.
Most importantly, this option MUST be included when the files are checked in for the first time. Once they are checked in without this flag, fixing the flag will not correct the damaged file on the server. If you checked in a binary file without this option, I recommend deleting it from the repository and checking in again.