small improvement in error logging

diff --git a/src/png2swf.c b/src/png2swf.c
index 609deca..bde8ebc 100644 (file)
--- a/src/png2swf.c
+++ b/src/png2swf.c
@@ -558,7 +558,7 @@ TAG *MovieAddFrame(SWF * swf, TAG * t, char *sname, int id)
     }
     
     if(!zimagedata || uncompress(imagedata, &imagedatalen, zimagedata, zimagedatalen) != Z_OK) {
-       fprintf(stderr, "Couldn't uncompress %s!\n", sname);
+       fprintf(stderr, "Couldn't uncompress IDAT chunk (%d bytes) in %s!\n", imagedatalen, sname);
        if(zimagedata)
            free(zimagedata);
        return 0;