c# - Ghostscript increases file size after split PDF -

i splitting pdf file images , working fine, issue have pdf file it's size 2.5 mb after splitting file images total size increases 8 mb. don't want increase these images size because storage issue on server.

code

using (var pdfreader = new pdfreader(filesavepath)) {     var imagelst = new pdf2image(filesavepath).getimages(1, pdfreader.numberofpages);     foreach (var image in imagelst)     {         imagemodal = new imagemodel();         imagemodal.filename = guid.newguid().tostring() + ".png";         image.save(dirpath + "\\" + imagemodal.filename);                //using below commented code can decrease image size 50 % percent creates image quality problem.          //int newwidth = (int)(image.width * 0.5);         //int newheight = (int)(image.height * 0.5);         //var newimage = imagehelper.resizeimage(image, newwidth, newheight);         //newimage.save(dirpath + "\\" + imagemodal.filename);         imagemodellist.add(imagemodal);     } } 

pdf files vector descriptions of page layout. image files bitmaps. 1 of reasons vector descriptions popular because more compact bitmaps.

if bitmaps large can reduce resolution @ render them, reduces quality.

other that, expectations seem unrealistic. image file going larger vector file.