Can graphics files be infected with a virus?

Most graphics files, however, contain only static

data and no executable code. The code that reads, writes, and displays

graphics data is found in translation and display programs and not in the

graphics files themselves. If reading or writing a graphics file caused a

system malfunction is it most likely the fault of the program reading the

file and not of the graphics file data itself.

With the introduction of multimedia we have seen new formats appear, and

modifications to older formats made, that allow executable instructions to

be stored within a file format. These instructions are used to direct

multimedia applications to play sounds or music, prompt the user for

information, or display other graphics and video information. And such

multimedia display programs may perform these functions by interfacing

with their environment via an API, or by direct interaction with the

operating system. One might also imagine a truly object-oriented graphics

file as containing the code required to read, write, and display itself.

Once again, any catastrophes that result from using these multimedia

application is most like the result of unfound bugs in the software and

not some sinister instructions in the graphics file data. Such "logic

bombs" are typically exorcised through the use of testing using a wide

variety of different image files for test cases.

If you have a virus scanning program that indicates a specific graphics

file is infected by virus, then it is very possible that the file

coincidentally contains a byte pattern that the scanning programming

recognizes as a key byte signature identifying a virus. Contact the author

(or even read the documentation!) of the virus scanning program to discuss

the probability of the mis-identification of a clean file as being

infected by a virus. Save the graphics file, as the author will most

likely wish to examine it as well.

If you suspect a graphics file to be at the heart of a virus problem you

are experiencing, then also consider the possibility that the graphics

file's transport mechanism (floppy disk, tape or shell archive file,

compressed archive file, and so forth) might be the original source of the

virus and not the graphics file itself.