If I recall correctly, there is a problem with the phpThumb library when you try to use zc=1 in combination with the crop options sx, sy, sw and sh. The image gets distorted.
Take a look a this topic:
If I recall correctly, there is a problem with the phpThumb library when you try to use zc=1 in combination with the crop options sx, sy, sw and sh. The image gets distorted.
Take a look a this topic: