I found a major bug for resizing images.
If in our admin control panel, on "MEDIA", we set 640X80 rather than writing 640x80 (X uppercase instead of lowercase), bypasses resizing images, and this create a bug with resizer image and GD library.
Inadvertently if the "x" does not write in lowercase, we could bang your head to find a solution when it comes to staying instead only pay attention to upper or lower case.
Try it to believe it .......
(AAAAAAAAARGH!!!!!!)