Image Editor Blocks

Hai everybody…

i wnt to ask about image editor blocks…I try to make watermark on image from camera, and its work to make watermark on image…but the problem is the size of the image that have watermark is always reduced…i already test image with and wihtout watermark, and it is have different size. Watermark image always resize the image…
is there any solution how to watermarking without reduce the size?

Thanks