JPEG closes frees FILE pointer upon unsuccessfull load, don't free it again.
Lubomir Rintel <lkundrak@v3.sk>

--- Mosaic-src.orig/src/picread.c	1996-06-27 00:57:12.000000000 +0200
+++ Mosaic-src/src/picread.c	2008-11-28 18:15:03.000000000 +0100
@@ -702,6 +702,10 @@ int *bg;
 		    if (fp != stdin) fclose(fp);
 		    return(bit_data);
 		}
+            else
+                {
+                    fp = NULL;
+                }
 #endif
 
 	}