Not binary image.
In reference to software, "source" is invariably shorthand for "source code", the preferred human-readable and human-modifiable form of the program. This is as opposed to object code, the derived binary executable form of a program. This shorthand readily takes derivative forms; one may speak of "the sources of a system" or of "having source".
In a high-level programming language, the typed program instructions that progammers write before the program is compiled or interpreted into machine language instructions the computer can execute.
Programming commands in their raw state as input by a programmer. Some programming languages allow the commands to be executed on the fly by a program interpreter. Other languages require the commands to be compiled into executable programs (binaries) before they can be used. In the UNIX/Linux world, some software is distributed as source code only; other packages include both source and binaries; still others are distributed in binary format only.
Specially written instructions by a software programmer to create executable programs when run through a compiler or language interpreter.
The form in which a computer program is written by the programmer. Source code is written in some formal programming language which can be compiled automatically into object code (into executable file) or machine code or executed by an interpreter.
In Linux, the source code is compiled into an executable file (binary).
*.src is a source code file.