I'll take a wild stab at this...

Is the image garbled after the 1024th byte (or some multiple thereof), perhaps? I always have to look up how to handle binary information in Perl and don't have a reference handy, but I'll bet the .= operator does not always Do The Right Thing (TM) with binary data. You know the size of the file - try reading the whole thing in all at once. Or use pack.

---

Update
Another possibility - you may need to set your output handle to binmode as well... Here's a snippet

$gifname = "picture.gif";
open(GIF, $gifname)         or die "can't open $gifname: $!";
 
binmode(GIF);          # now DOS won't mangle binary input from GIF
binmode(STDOUT);       # now DOS won't mangle binary output to STDOUT
 
while (read(GIF, $buff, 8 * 2**10)) {
    print STDOUT $buff;
}
[download]

that looks like it does exactly what you want. I found it in the O'Reilly Perl Cookbook Sample Chapter 8. O'Reilly rocks.

---

Update 2
On second thought, the snippet still doesn't handle the problem of concatenating binary data. Oh well.