You can add custom option by choosing "File" and file types "jpg,jpeg,png".
But is there an extension for simple image manipulation of brightness/contrast?
If not, how to add it?
Do you want to be able to edit, for example, bright and contrast of images uploaded to the products?
The edition should apply per picture? I mean, do you want to be able to edit picture by picture to change those values?
I want to add brightness, contrast, cropping to product view custom options. (The customer uploads image when order.)