saving images into pdf file using PDFlib

Hi im saving image into pdf with: $image = pdf_load_image($p, 'jpeg', $picture_path, ""); pdf_fit_image($p, $image, $x_im, $y_im, ""); pdf_close_image($p, $image); image is 150px x 100px but in genereted pdf file it looks much smaller. im viewing mentioned pdf file with 100% view ratio. i've tried it with several other images and im getting same result. any idea what's wrong ? i tried workaround with: pdf_fit_image($p, $image, $x_im, $y_im, "boxsize {150 100} position 0 fitmethod meet"); however it doesnt look so good thanks Jan