script for " turn the pdf to img with compression".

some code are borrowed from this url

most scripts need GhostScript 9.26, you can find it on here

cropimg.m : crop imgs for a folder

pdf2img: convert pdf to imgs(most of formats of image)

compress_pdf.m: compress the pdf with user-defined dpi, you can change the parameter 'xxxxResolution'

remove the background, please refer to this link