Custom image manipulations

[morawcik]

Hi, I have defined couple of conversions for model and it works great but in some cases I want to do something more with images (like crop image to cut off big white background and add small paddings/margins to image or blur text in image). I can do it directly for image (for e.g with GD) but i would love to use in conversion to have it done at once when conversion is running and not with custom task/command. How I could do that?