Correct logic

Co-authored-by: Hugo van Kemenade <1324225+hugovk@users.noreply.github.com>

Author: radarhere

src/PIL/Image.py

@@ -3690,7 +3690,7 @@ def _open_core(
                 raise
         return None
 
-    if im := _open_core(fp, filename, prefix, ID):
+    if not (im := _open_core(fp, filename, prefix, ID)):
         # Try preinit (few common plugins) then init (all plugins)
         for loader in (preinit, init):
             checked_formats = ID.copy()